diff --git a/immediate_stats/src/bevy.rs b/immediate_stats/src/bevy.rs
--- a/immediate_stats/src/bevy.rs
+++ b/immediate_stats/src/bevy.rs
@@ -1,9 +1,6 @@
-#[cfg(feature = "bevy_butler")]
-pub mod butler;
-
 use crate::StatContainer;
+use crate::modifier::Modifier;
 use crate::stat::Stat;
-use crate::stat::modifier::Modifier;
 use bevy_app::{App, Plugin};
 use bevy_ecs::component::Mutable;
 use bevy_ecs::prelude::ReflectComponent;
@@ -38,74 +35,5 @@
 pub fn reset_resource_modifiers<T: Resource + StatContainer>(res: Option<ResMut<T>>) {
     if let Some(mut res) = res {
         res.reset_modifiers();
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::stat::Stat;
-    use bevy_ecs::prelude::World;
-    use immediate_stats_macros::StatContainer;
-
-    #[derive(Component, Resource, StatContainer, PartialEq, Debug, Clone)]
-    struct Health(Stat);
-
-    #[test]
-    fn reset_component() {
-        let mut world = World::new();
-        let system = world.register_system(reset_component_modifiers::<Health>);
-
-        let entity = world
-            .spawn(Health(Stat {
-                base: 100,
-                bonus: 50,
-                multiplier: 2.0,
-            }))
-            .id();
-
-        world.run_system(system).unwrap();
-
-        assert_eq!(
-            world.get::<Health>(entity),
-            Some(Health(Stat::new(100))).as_ref()
-        );
-    }
-
-    #[test]
-    fn pause_component() {
-        let mut world = World::new();
-        let system = world.register_system(reset_component_modifiers::<Health>);
-
-        let health = Health(Stat {
-            base: 100,
-            bonus: 50,
-            multiplier: 2.0,
-        });
-
-        let entity = world.spawn((health.clone(), PauseStatReset)).id();
-
-        world.run_system(system).unwrap();
-
-        assert_eq!(world.get::<Health>(entity), Some(health).as_ref());
-    }
-
-    #[test]
-    fn reset_resource() {
-        let mut world = World::new();
-        let system = world.register_system(reset_resource_modifiers::<Health>);
-
-        world.insert_resource(Health(Stat {
-            base: 100,
-            bonus: 50,
-            multiplier: 2.0,
-        }));
-
-        world.run_system(system).unwrap();
-
-        assert_eq!(
-            world.get_resource::<Health>(),
-            Some(Health(Stat::new(100))).as_ref()
-        );
     }
 }
diff --git a/immediate_stats/src/lib.rs b/immediate_stats/src/lib.rs
--- a/immediate_stats/src/lib.rs
+++ b/immediate_stats/src/lib.rs
@@ -2,6 +2,7 @@
 
 #[cfg(feature = "bevy")]
 pub mod bevy;
+pub mod modifier;
 pub mod stat;
 
 // Todo Move into internal module called `__internal` like Bevy Butler.
@@ -11,6 +12,7 @@
 
 #[cfg(feature = "bevy")]
 pub use bevy::*;
+pub use modifier::*;
 pub use stat::*;
 
 /// Types that contain stats that need to be reset.
@@ -22,171 +24,4 @@
 pub trait StatContainer {
     /// Resets all stat bonuses to zero, and stat multipliers to one.
     fn reset_modifiers(&mut self);
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::stat::Stat;
-    use immediate_stats_macros::StatContainer;
-
-    #[derive(StatContainer, PartialEq, Debug)]
-    struct Movement {
-        speed: Stat,
-        other: bool,
-    }
-
-    #[test]
-    fn reset() {
-        for base in 0..10 {
-            let mut movement = Movement {
-                speed: Stat {
-                    base,
-                    bonus: 3,
-                    multiplier: 1.5,
-                },
-                other: true,
-            };
-
-            movement.reset_modifiers();
-
-            assert_eq!(
-                movement,
-                Movement {
-                    speed: Stat::new(base),
-                    other: true
-                }
-            );
-        }
-    }
-
-    #[derive(StatContainer, PartialEq, Debug)]
-    struct MaxHealth(Stat, bool);
-
-    #[test]
-    fn reset_tuple_struct() {
-        for base in 0..10 {
-            let mut max_health = MaxHealth(
-                Stat {
-                    base,
-                    bonus: 3,
-                    multiplier: 1.5,
-                },
-                true,
-            );
-
-            max_health.reset_modifiers();
-
-            assert_eq!(max_health.0, Stat::new(base));
-        }
-    }
-
-    #[derive(StatContainer, PartialEq, Debug)]
-    struct Health {
-        #[stat]
-        max: MaxHealth,
-        current: i32,
-    }
-
-    #[test]
-    fn reset_with_attribute() {
-        for base in 0..10 {
-            let mut health = Health {
-                max: MaxHealth(
-                    Stat {
-                        base,
-                        bonus: 3,
-                        multiplier: 1.5,
-                    },
-                    true,
-                ),
-                current: base,
-            };
-
-            health.reset_modifiers();
-
-            assert_eq!(health.max.0, Stat::new(base));
-        }
-    }
-
-    #[derive(StatContainer, PartialEq, Debug)]
-    struct PartialReset {
-        #[stat_ignore]
-        ignored: Stat,
-        reset: Stat,
-    }
-
-    #[test]
-    fn reset_ignored() {
-        for base in 0..10 {
-            let stat = Stat {
-                base,
-                bonus: 3,
-                multiplier: 1.5,
-            };
-
-            let mut partial = PartialReset {
-                ignored: stat,
-                reset: stat,
-            };
-
-            partial.reset_modifiers();
-
-            assert_eq!(partial.ignored, stat);
-            assert_eq!(partial.reset, Stat::new(base));
-        }
-    }
-
-    #[derive(StatContainer, PartialEq, Debug)]
-    enum EnumStat {
-        Named {
-            stat: Stat,
-            other: u8,
-        },
-        Unnamed(Stat, u8),
-        #[expect(dead_code)]
-        Other,
-    }
-
-    #[test]
-    fn reset_enum_named() {
-        for base in 0..10 {
-            let mut stat = EnumStat::Named {
-                stat: Stat {
-                    base,
-                    bonus: 3,
-                    multiplier: 1.5,
-                },
-                other: 0,
-            };
-
-            stat.reset_modifiers();
-
-            assert_eq!(
-                stat,
-                EnumStat::Named {
-                    stat: Stat::new(base),
-                    other: 0,
-                }
-            );
-        }
-    }
-
-    #[test]
-    fn reset_enum_unnamed() {
-        for base in 0..10 {
-            let mut stat = EnumStat::Unnamed(
-                Stat {
-                    base,
-                    bonus: 3,
-                    multiplier: 1.5,
-                },
-                0,
-            );
-
-            stat.reset_modifiers();
-
-            assert_eq!(stat, EnumStat::Unnamed(Stat::new(base), 0));
-        }
-    }
 }
diff --git a/immediate_stats/src/modifier.rs b/immediate_stats/src/modifier.rs
new file mode 100644
--- /dev/null
+++ b/immediate_stats/src/modifier.rs
@@ -0,0 +1,68 @@
+use std::ops::{AddAssign, DivAssign, MulAssign, SubAssign};
+
+/// Modifier values that can be applied to a [`super::Stat`].
+#[derive(PartialEq, Debug, Copy, Clone)]
+#[cfg_attr(
+    feature = "bevy",
+    derive(bevy_reflect::Reflect),
+    reflect(PartialEq, Debug, Clone)
+)]
+pub struct Modifier {
+    /// Added to `base` of a [`super::Stat`] during calculation.
+    pub bonus: i32,
+    /// Multiplies the `base` of a [`super::Stat`] during calculation.
+    pub multiplier: f32,
+}
+
+impl Modifier {
+    pub fn new(bonus: i32, multiplier: f32) -> Self {
+        Self { bonus, multiplier }
+    }
+
+    pub fn from_bonus(bonus: i32) -> Self {
+        Self {
+            bonus,
+            ..Self::default()
+        }
+    }
+
+    pub fn from_multiplier(multiplier: f32) -> Self {
+        Self {
+            multiplier,
+            ..Self::default()
+        }
+    }
+}
+
+impl Default for Modifier {
+    fn default() -> Self {
+        Self {
+            bonus: 0,
+            multiplier: 1.0,
+        }
+    }
+}
+
+impl AddAssign<i32> for Modifier {
+    fn add_assign(&mut self, rhs: i32) {
+        self.bonus += rhs;
+    }
+}
+
+impl SubAssign<i32> for Modifier {
+    fn sub_assign(&mut self, rhs: i32) {
+        self.bonus -= rhs;
+    }
+}
+
+impl MulAssign<f32> for Modifier {
+    fn mul_assign(&mut self, rhs: f32) {
+        self.multiplier *= rhs;
+    }
+}
+
+impl DivAssign<f32> for Modifier {
+    fn div_assign(&mut self, rhs: f32) {
+        self.multiplier /= rhs;
+    }
+}
diff --git a/immediate_stats/src/stat.rs b/immediate_stats/src/stat.rs
--- a/immediate_stats/src/stat.rs
+++ b/immediate_stats/src/stat.rs
@@ -1,7 +1,5 @@
-pub mod modifier;
-
 use crate::StatContainer;
-use crate::stat::modifier::Modifier;
+use crate::modifier::Modifier;
 use std::ops::{AddAssign, DivAssign, MulAssign, SubAssign};
 
 /// A stat that [resets] to a base value every iteration.
@@ -114,132 +112,5 @@
 impl DivAssign<f32> for Stat {
     fn div_assign(&mut self, rhs: f32) {
         self.multiplier /= rhs;
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn reset() {
-        for i in 0..10 {
-            let mut stat = Stat {
-                base: i,
-                bonus: 4,
-                multiplier: 1.5,
-            };
-            stat.reset_modifiers();
-
-            assert_eq!(stat, Stat::new(i));
-        }
-    }
-
-    #[test]
-    fn add() {
-        let mut stat = Stat::new(10);
-        stat += 5;
-        assert_eq!(
-            stat,
-            Stat {
-                base: 10,
-                bonus: 5,
-                multiplier: 1.0,
-            }
-        );
-    }
-
-    #[test]
-    fn subtract() {
-        let mut stat = Stat::new(10);
-        stat -= 5;
-        assert_eq!(
-            stat,
-            Stat {
-                base: 10,
-                bonus: -5,
-                multiplier: 1.0,
-            }
-        );
-    }
-
-    #[test]
-    fn multiply() {
-        let mut stat = Stat::new(10);
-        stat *= 2.0;
-        assert_eq!(
-            stat,
-            Stat {
-                base: 10,
-                bonus: 0,
-                multiplier: 2.0,
-            }
-        );
-    }
-
-    #[test]
-    fn divide() {
-        let mut stat = Stat::new(10);
-        stat /= 2.0;
-        assert_eq!(
-            stat,
-            Stat {
-                base: 10,
-                bonus: 0,
-                multiplier: 0.5,
-            }
-        );
-    }
-
-    #[test]
-    fn default_total() {
-        for i in 0..10 {
-            assert_eq!(Stat::new(i).total(), i);
-        }
-    }
-
-    #[test]
-    fn total() {
-        assert_eq!(
-            Stat {
-                base: 10,
-                bonus: 4,
-                multiplier: 1.5,
-            }
-            .total(),
-            21
-        )
-    }
-
-    #[test]
-    fn total_no_bonus() {
-        assert_eq!(Stat::new(20).with_multiplier(0.5).total(), 10);
-    }
-
-    #[test]
-    fn total_no_multiplier() {
-        assert_eq!(Stat::new(2).with_bonus(1).total(), 3);
-    }
-
-    #[test]
-    fn total_with_modifier() {
-        assert_eq!(Stat::new(5).with_modifier(Modifier::new(1, 0.5)).total(), 3);
-    }
-
-    #[test]
-    fn apply() {
-        let mut stat = Stat::new(10);
-
-        stat.apply(Modifier::new(2, 2.0));
-        stat.apply(Modifier::new(3, 4.0));
-
-        assert_eq!(
-            stat,
-            Stat {
-                base: 10,
-                bonus: 5,
-                multiplier: 8.0,
-            }
-        )
     }
 }
diff --git a/immediate_stats/tests/bevy.rs b/immediate_stats/tests/bevy.rs
new file mode 100644
--- /dev/null
+++ b/immediate_stats/tests/bevy.rs
@@ -0,0 +1,66 @@
+#![cfg(feature = "bevy")]
+//! Tests the reset systems and `PauseStatReset`.
+
+use bevy_ecs::prelude::*;
+use immediate_stats::*;
+
+#[derive(Component, Resource, StatContainer, PartialEq, Debug, Clone)]
+struct Health(Stat);
+
+#[test]
+fn reset_component() {
+    let mut world = World::new();
+    let system = world.register_system(reset_component_modifiers::<Health>);
+
+    let entity = world
+        .spawn(Health(Stat {
+            base: 100,
+            bonus: 50,
+            multiplier: 2.0,
+        }))
+        .id();
+
+    world.run_system(system).unwrap();
+
+    assert_eq!(
+        world.get::<Health>(entity),
+        Some(Health(Stat::new(100))).as_ref()
+    );
+}
+
+#[test]
+fn pause_component() {
+    let mut world = World::new();
+    let system = world.register_system(reset_component_modifiers::<Health>);
+
+    let health = Health(Stat {
+        base: 100,
+        bonus: 50,
+        multiplier: 2.0,
+    });
+
+    let entity = world.spawn((health.clone(), PauseStatReset)).id();
+
+    world.run_system(system).unwrap();
+
+    assert_eq!(world.get::<Health>(entity), Some(health).as_ref());
+}
+
+#[test]
+fn reset_resource() {
+    let mut world = World::new();
+    let system = world.register_system(reset_resource_modifiers::<Health>);
+
+    world.insert_resource(Health(Stat {
+        base: 100,
+        bonus: 50,
+        multiplier: 2.0,
+    }));
+
+    world.run_system(system).unwrap();
+
+    assert_eq!(
+        world.get_resource::<Health>(),
+        Some(Health(Stat::new(100))).as_ref()
+    );
+}
diff --git a/immediate_stats/tests/bevy_butler.rs b/immediate_stats/tests/bevy_butler.rs
new file mode 100644
--- /dev/null
+++ b/immediate_stats/tests/bevy_butler.rs
@@ -0,0 +1,60 @@
+#![cfg(feature = "bevy_butler")]
+//! Tests the `add_component` attribute for automatic system registration.
+
+use crate::StatContainer;
+use crate::stat::Stat;
+use bevy_app::App;
+use bevy_butler::*;
+use bevy_ecs::prelude::*;
+use immediate_stats::*;
+
+#[butler_plugin]
+struct MyPlugin;
+
+#[derive(Resource, Component, StatContainer, Default, PartialEq, Debug)]
+#[add_component(plugin = MyPlugin)]
+#[add_resource(plugin = MyPlugin)]
+struct Health(Stat);
+
+#[test]
+fn reset_component_auto() {
+    let mut app = App::new();
+
+    app.add_plugins(MyPlugin);
+
+    let entity = app
+        .world_mut()
+        .spawn(Health(Stat {
+            base: 100,
+            bonus: 50,
+            multiplier: 2.0,
+        }))
+        .id();
+
+    app.update();
+
+    assert_eq!(
+        app.world().get::<Health>(entity),
+        Some(Health(Stat::new(100))).as_ref()
+    );
+}
+
+#[test]
+fn reset_resource_auto() {
+    let mut app = App::new();
+
+    app.add_plugins(MyPlugin);
+
+    app.insert_resource(Health(Stat {
+        base: 100,
+        bonus: 50,
+        multiplier: 2.0,
+    }));
+
+    app.update();
+
+    assert_eq!(
+        app.world().get_resource::<Health>(),
+        Some(Health(Stat::new(100))).as_ref()
+    );
+}
diff --git a/immediate_stats/tests/derive.rs b/immediate_stats/tests/derive.rs
new file mode 100644
--- /dev/null
+++ b/immediate_stats/tests/derive.rs
@@ -0,0 +1,163 @@
+//! Tests the basic `StatContainer` derive with no extra features.
+
+use immediate_stats::*;
+
+#[derive(StatContainer, PartialEq, Debug)]
+struct Movement {
+    speed: Stat,
+    other: bool,
+}
+
+#[test]
+fn reset() {
+    for base in 0..10 {
+        let mut movement = Movement {
+            speed: Stat {
+                base,
+                bonus: 3,
+                multiplier: 1.5,
+            },
+            other: true,
+        };
+
+        movement.reset_modifiers();
+
+        assert_eq!(
+            movement,
+            Movement {
+                speed: Stat::new(base),
+                other: true
+            }
+        );
+    }
+}
+
+#[derive(StatContainer, PartialEq, Debug)]
+struct MaxHealth(Stat, bool);
+
+#[test]
+fn reset_tuple_struct() {
+    for base in 0..10 {
+        let mut max_health = MaxHealth(
+            Stat {
+                base,
+                bonus: 3,
+                multiplier: 1.5,
+            },
+            true,
+        );
+
+        max_health.reset_modifiers();
+
+        assert_eq!(max_health.0, Stat::new(base));
+    }
+}
+
+#[derive(StatContainer, PartialEq, Debug)]
+struct Health {
+    #[stat]
+    max: MaxHealth,
+    current: i32,
+}
+
+#[test]
+fn reset_with_attribute() {
+    for base in 0..10 {
+        let mut health = Health {
+            max: MaxHealth(
+                Stat {
+                    base,
+                    bonus: 3,
+                    multiplier: 1.5,
+                },
+                true,
+            ),
+            current: base,
+        };
+
+        health.reset_modifiers();
+
+        assert_eq!(health.max.0, Stat::new(base));
+    }
+}
+
+#[derive(StatContainer, PartialEq, Debug)]
+struct PartialReset {
+    #[stat_ignore]
+    ignored: Stat,
+    reset: Stat,
+}
+
+#[test]
+fn reset_ignored() {
+    for base in 0..10 {
+        let stat = Stat {
+            base,
+            bonus: 3,
+            multiplier: 1.5,
+        };
+
+        let mut partial = PartialReset {
+            ignored: stat,
+            reset: stat,
+        };
+
+        partial.reset_modifiers();
+
+        assert_eq!(partial.ignored, stat);
+        assert_eq!(partial.reset, Stat::new(base));
+    }
+}
+
+#[derive(StatContainer, PartialEq, Debug)]
+enum EnumStat {
+    Named {
+        stat: Stat,
+        other: u8,
+    },
+    Unnamed(Stat, u8),
+    #[expect(dead_code)]
+    Other,
+}
+
+#[test]
+fn reset_enum_named() {
+    for base in 0..10 {
+        let mut stat = EnumStat::Named {
+            stat: Stat {
+                base,
+                bonus: 3,
+                multiplier: 1.5,
+            },
+            other: 0,
+        };
+
+        stat.reset_modifiers();
+
+        assert_eq!(
+            stat,
+            EnumStat::Named {
+                stat: Stat::new(base),
+                other: 0,
+            }
+        );
+    }
+}
+
+#[test]
+fn reset_enum_unnamed() {
+    for base in 0..10 {
+        let mut stat = EnumStat::Unnamed(
+            Stat {
+                base,
+                bonus: 3,
+                multiplier: 1.5,
+            },
+            0,
+        );
+
+        stat.reset_modifiers();
+
+        assert_eq!(stat, EnumStat::Unnamed(Stat::new(base), 0));
+    }
+}
diff --git a/immediate_stats/tests/modifier.rs b/immediate_stats/tests/modifier.rs
new file mode 100644
--- /dev/null
+++ b/immediate_stats/tests/modifier.rs
@@ -0,0 +1,55 @@
+//! Tests the various methods of `Modifier`.
+
+use immediate_stats::*;
+
+#[test]
+fn add() {
+    let mut modifier = Modifier::default();
+    modifier += 5;
+    assert_eq!(
+        modifier,
+        Modifier {
+            bonus: 5,
+            multiplier: 1.0,
+        }
+    );
+}
+
+#[test]
+fn subtract() {
+    let mut modifier = Modifier::default();
+    modifier -= 5;
+    assert_eq!(
+        modifier,
+        Modifier {
+            bonus: -5,
+            multiplier: 1.0,
+        }
+    );
+}
+
+#[test]
+fn multiply() {
+    let mut modifier = Modifier::default();
+    modifier *= 2.0;
+    assert_eq!(
+        modifier,
+        Modifier {
+            bonus: 0,
+            multiplier: 2.0,
+        }
+    );
+}
+
+#[test]
+fn divide() {
+    let mut modifier = Modifier::default();
+    modifier /= 2.0;
+    assert_eq!(
+        modifier,
+        Modifier {
+            bonus: 0,
+            multiplier: 0.5,
+        }
+    );
+}
diff --git a/immediate_stats/tests/stat.rs b/immediate_stats/tests/stat.rs
new file mode 100644
--- /dev/null
+++ b/immediate_stats/tests/stat.rs
@@ -0,0 +1,125 @@
+//! Tests the various methods of `Stat`.
+
+use immediate_stats::*;
+
+#[test]
+fn reset() {
+    for i in 0..10 {
+        let mut stat = Stat {
+            base: i,
+            bonus: 4,
+            multiplier: 1.5,
+        };
+        stat.reset_modifiers();
+
+        assert_eq!(stat, Stat::new(i));
+    }
+}
+
+#[test]
+fn add() {
+    let mut stat = Stat::new(10);
+    stat += 5;
+    assert_eq!(
+        stat,
+        Stat {
+            base: 10,
+            bonus: 5,
+            multiplier: 1.0,
+        }
+    );
+}
+
+#[test]
+fn subtract() {
+    let mut stat = Stat::new(10);
+    stat -= 5;
+    assert_eq!(
+        stat,
+        Stat {
+            base: 10,
+            bonus: -5,
+            multiplier: 1.0,
+        }
+    );
+}
+
+#[test]
+fn multiply() {
+    let mut stat = Stat::new(10);
+    stat *= 2.0;
+    assert_eq!(
+        stat,
+        Stat {
+            base: 10,
+            bonus: 0,
+            multiplier: 2.0,
+        }
+    );
+}
+
+#[test]
+fn divide() {
+    let mut stat = Stat::new(10);
+    stat /= 2.0;
+    assert_eq!(
+        stat,
+        Stat {
+            base: 10,
+            bonus: 0,
+            multiplier: 0.5,
+        }
+    );
+}
+
+#[test]
+fn default_total() {
+    for i in 0..10 {
+        assert_eq!(Stat::new(i).total(), i);
+    }
+}
+
+#[test]
+fn total() {
+    assert_eq!(
+        Stat {
+            base: 10,
+            bonus: 4,
+            multiplier: 1.5,
+        }
+        .total(),
+        21
+    )
+}
+
+#[test]
+fn total_no_bonus() {
+    assert_eq!(Stat::new(20).with_multiplier(0.5).total(), 10);
+}
+
+#[test]
+fn total_no_multiplier() {
+    assert_eq!(Stat::new(2).with_bonus(1).total(), 3);
+}
+
+#[test]
+fn total_with_modifier() {
+    assert_eq!(Stat::new(5).with_modifier(Modifier::new(1, 0.5)).total(), 3);
+}
+
+#[test]
+fn apply() {
+    let mut stat = Stat::new(10);
+
+    stat.apply(Modifier::new(2, 2.0));
+    stat.apply(Modifier::new(3, 4.0));
+
+    assert_eq!(
+        stat,
+        Stat {
+            base: 10,
+            bonus: 5,
+            multiplier: 8.0,
+        }
+    )
+}
diff --git a/immediate_stats/src/bevy/butler.rs b/immediate_stats/src/bevy/butler.rs
deleted file mode 100644
--- a/immediate_stats/src/bevy/butler.rs
+++ /dev/null
@@ -1,60 +0,0 @@
-#[cfg(test)]
-mod tests {
-    use crate as immediate_stats;
-    use crate::StatContainer;
-    use crate::stat::Stat;
-    use bevy_app::App;
-    use bevy_butler::*;
-    use bevy_ecs::prelude::*;
-
-    #[butler_plugin]
-    struct MyPlugin;
-
-    #[derive(Resource, Component, StatContainer, Default, PartialEq, Debug)]
-    #[add_component(plugin = MyPlugin)]
-    #[add_resource(plugin = MyPlugin)]
-    struct Health(Stat);
-
-    #[test]
-    fn reset_component_auto() {
-        let mut app = App::new();
-
-        app.add_plugins(MyPlugin);
-
-        let entity = app
-            .world_mut()
-            .spawn(Health(Stat {
-                base: 100,
-                bonus: 50,
-                multiplier: 2.0,
-            }))
-            .id();
-
-        app.update();
-
-        assert_eq!(
-            app.world().get::<Health>(entity),
-            Some(Health(Stat::new(100))).as_ref()
-        );
-    }
-
-    #[test]
-    fn reset_resource_auto() {
-        let mut app = App::new();
-
-        app.add_plugins(MyPlugin);
-
-        app.insert_resource(Health(Stat {
-            base: 100,
-            bonus: 50,
-            multiplier: 2.0,
-        }));
-
-        app.update();
-
-        assert_eq!(
-            app.world().get_resource::<Health>(),
-            Some(Health(Stat::new(100))).as_ref()
-        );
-    }
-}
diff --git a/immediate_stats/src/stat/modifier.rs b/immediate_stats/src/stat/modifier.rs
deleted file mode 100644
--- a/immediate_stats/src/stat/modifier.rs
+++ /dev/null
@@ -1,125 +0,0 @@
-use std::ops::{AddAssign, DivAssign, MulAssign, SubAssign};
-
-/// Modifier values that can be applied to a [`super::Stat`].
-#[derive(PartialEq, Debug, Copy, Clone)]
-#[cfg_attr(
-    feature = "bevy",
-    derive(bevy_reflect::Reflect),
-    reflect(PartialEq, Debug, Clone)
-)]
-pub struct Modifier {
-    /// Added to `base` of a [`super::Stat`] during calculation.
-    pub bonus: i32,
-    /// Multiplies the `base` of a [`super::Stat`] during calculation.
-    pub multiplier: f32,
-}
-
-impl Modifier {
-    pub fn new(bonus: i32, multiplier: f32) -> Self {
-        Self { bonus, multiplier }
-    }
-
-    pub fn from_bonus(bonus: i32) -> Self {
-        Self {
-            bonus,
-            ..Self::default()
-        }
-    }
-
-    pub fn from_multiplier(multiplier: f32) -> Self {
-        Self {
-            multiplier,
-            ..Self::default()
-        }
-    }
-}
-
-impl Default for Modifier {
-    fn default() -> Self {
-        Self {
-            bonus: 0,
-            multiplier: 1.0,
-        }
-    }
-}
-
-impl AddAssign<i32> for Modifier {
-    fn add_assign(&mut self, rhs: i32) {
-        self.bonus += rhs;
-    }
-}
-
-impl SubAssign<i32> for Modifier {
-    fn sub_assign(&mut self, rhs: i32) {
-        self.bonus -= rhs;
-    }
-}
-
-impl MulAssign<f32> for Modifier {
-    fn mul_assign(&mut self, rhs: f32) {
-        self.multiplier *= rhs;
-    }
-}
-
-impl DivAssign<f32> for Modifier {
-    fn div_assign(&mut self, rhs: f32) {
-        self.multiplier /= rhs;
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn add() {
-        let mut modifier = Modifier::default();
-        modifier += 5;
-        assert_eq!(
-            modifier,
-            Modifier {
-                bonus: 5,
-                multiplier: 1.0,
-            }
-        );
-    }
-
-    #[test]
-    fn subtract() {
-        let mut modifier = Modifier::default();
-        modifier -= 5;
-        assert_eq!(
-            modifier,
-            Modifier {
-                bonus: -5,
-                multiplier: 1.0,
-            }
-        );
-    }
-
-    #[test]
-    fn multiply() {
-        let mut modifier = Modifier::default();
-        modifier *= 2.0;
-        assert_eq!(
-            modifier,
-            Modifier {
-                bonus: 0,
-                multiplier: 2.0,
-            }
-        );
-    }
-
-    #[test]
-    fn divide() {
-        let mut modifier = Modifier::default();
-        modifier /= 2.0;
-        assert_eq!(
-            modifier,
-            Modifier {
-                bonus: 0,
-                multiplier: 0.5,
-            }
-        );
-    }
-}