diff --git a/package.json b/package.json
index f4e6803a..17e333f7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "tof-tools",
-  "version": "3.12.0",
+  "version": "3.13.0",
   "private": true,
   "scripts": {
     "dev": "next dev",
diff --git a/public/icons/weapons/rei.png b/public/icons/weapons/rei.png
new file mode 100644
index 00000000..1ec0fecc
Binary files /dev/null and b/public/icons/weapons/rei.png differ
diff --git a/src/constants/changelog.tsx b/src/constants/changelog.tsx
index 286508a2..0edd16ba 100644
--- a/src/constants/changelog.tsx
+++ b/src/constants/changelog.tsx
@@ -201,4 +201,9 @@ export const changelog: Changelog = [
     date: new Date(Date.UTC(2024, 2, 15)),
     title: 'Add a page containing useful links',
   },
+  {
+    semver: '3.13.0',
+    date: new Date(Date.UTC(2024, 2, 29)),
+    title: 'Add Rei',
+  },
 ];
diff --git a/src/constants/matrix-set-definitions.ts b/src/constants/matrix-set-definitions.ts
index a9fa6089..1727da71 100644
--- a/src/constants/matrix-set-definitions.ts
+++ b/src/constants/matrix-set-definitions.ts
@@ -37,6 +37,7 @@ export type MatrixSetBaseName =
   | 'Nan Yin'
   | 'Nemesis'
   | 'Plotti'
+  | 'Rei'
   | 'Rubilia'
   | 'Ruby'
   | 'Saki Fuwa'
@@ -80,6 +81,7 @@ export const matrixSet2pcOrder: DataAllIds<MatrixSet2pcName> = [
   'Nan Yin 2pc',
   'Nemesis 2pc',
   'Plotti 2pc',
+  'Rei 2pc',
   'Rubilia 2pc',
   'Ruby 2pc',
   'Saki Fuwa 2pc',
@@ -124,6 +126,7 @@ export const matrixSet4pcOrder: DataAllIds<MatrixSet4pcName> = [
   'Nan Yin 4pc',
   'Nemesis 4pc',
   'Plotti 4pc',
+  'Rei 4pc',
   'Rubilia 4pc',
   'Ruby 4pc',
   'Saki Fuwa 4pc',
@@ -566,6 +569,14 @@ export const matrixSetDefinitionsLookup: DataById<
     critRateBuffs: [],
     critDamageBuffs: [],
   },
+  'Rei 2pc': {
+    id: 'Rei 2pc',
+    displayName: 'Rei 2pc',
+    pieces: 2,
+    attackPercentBuffs: [],
+    critRateBuffs: [],
+    critDamageBuffs: [],
+  },
   'Rubilia 2pc': {
     id: 'Rubilia 2pc',
     displayName: 'Rubilia 2pc',
@@ -1072,6 +1083,29 @@ export const matrixSetDefinitionsLookup: DataById<
     critRateBuffs: [],
     critDamageBuffs: [],
   },
+  'Rei 4pc': {
+    id: 'Rei 4pc',
+    displayName: 'Rei 4pc',
+    pieces: 4,
+    attackPercentBuffs: [
+      {
+        description:
+          "After dealing damage with Rei's weapon, increase volt and frost ATK by 12% for 5 seconds",
+        starValues: [
+          { star: 0, value: 0.12 },
+          { star: 1, value: 0.12 },
+          { star: 2, value: 0.12 },
+          { star: 3, value: 0.12 },
+        ],
+        elementalTypes: ['Volt', 'Frost'],
+        canStack: false,
+        isActivePassively: false,
+        weaponRequirement: 'Rei',
+      },
+    ],
+    critRateBuffs: [],
+    critDamageBuffs: [],
+  },
   'Rubilia 4pc': {
     id: 'Rubilia 4pc',
     displayName: 'Rubilia 4pc',
diff --git a/src/constants/simulacrum-traits.ts b/src/constants/simulacrum-traits.ts
index 973508d4..8e684f9d 100644
--- a/src/constants/simulacrum-traits.ts
+++ b/src/constants/simulacrum-traits.ts
@@ -853,6 +853,50 @@ export const simulacrumTraits: Data<SimulacrumName, SimulacrumTrait> = {
         },
       ],
     },
+    Rei: {
+      id: 'Rei',
+      displayName: 'Rei',
+      attackBuffs: [],
+      damageBuffs: [
+        {
+          id: 'rei-trait',
+          displayName: 'Rei trait',
+          description: 'Increase final damage by 18%',
+          value: 0.18,
+          elementalTypes: ['Altered', 'Flame', 'Frost', 'Physical', 'Volt'],
+          damageCategory: '[TEMP_TRAIT]',
+          maxStacks: 1,
+          triggeredBy: {
+            combatStart: true,
+          },
+          duration: {
+            untilCombatEnd: true,
+          },
+          cooldown: 0,
+        },
+        {
+          id: 'rei-trait-attack-resonance',
+          displayName: 'Rei trait - Attack resonance',
+          description:
+            'Increase volt damage by 8% when Attack Resonance is activated',
+          value: 0.08,
+          elementalTypes: ['Volt'],
+          damageCategory: '[TEMP_TRAIT]',
+          maxStacks: 1,
+          triggeredBy: {
+            combatStart: true,
+          },
+          duration: {
+            untilCombatEnd: true,
+          },
+          cooldown: 0,
+          requirements: {
+            weaponResonance: 'Attack',
+          },
+        },
+      ],
+      miscellaneousBuffs: [],
+    },
     Rubilia: {
       id: 'Rubilia',
       displayName: 'Rubilia',
diff --git a/src/constants/weapon-definitions.ts b/src/constants/weapon-definitions.ts
index d3601f5d..7b603746 100644
--- a/src/constants/weapon-definitions.ts
+++ b/src/constants/weapon-definitions.ts
@@ -29,6 +29,7 @@ export type WeaponName =
   | 'Nan Yin'
   | 'Nemesis'
   | 'Plotti'
+  | 'Rei'
   | 'Rubilia'
   | 'Ruby'
   | 'Saki Fuwa'
@@ -71,6 +72,7 @@ export const weaponDefinitions: Data<WeaponName, WeaponDefinition> = {
     'Nan Yin',
     'Nemesis',
     'Plotti',
+    'Rei',
     'Rubilia',
     'Ruby',
     'Saki Fuwa',
@@ -1624,6 +1626,83 @@ export const weaponDefinitions: Data<WeaponName, WeaponDefinition> = {
       attackBuffs: [],
       damageBuffs: [],
     },
+    Rei: {
+      id: 'Rei',
+      displayName: 'Rei',
+      resonanceElements: ['Volt', 'Frost'],
+      damageElement: 'Volt',
+      type: 'DPS',
+      attackPercentBuffs: [
+        {
+          id: 'Volt Resonance',
+          displayName: 'Volt Resonance',
+          description: '+15% volt ATK when equipping 2 or more volt weapons',
+          value: 0.15,
+          elementalTypes: ['Volt'],
+          canStack: false,
+          isActivePassively: true,
+          minStarRequirement: 0,
+          maxStarRequirement: 6,
+          elementalResonanceRequirements: ['Volt'],
+        },
+        {
+          id: 'Frost Resonance',
+          displayName: 'Frost Resonance',
+          description: '+15% frost ATK when equipping 2 or more frost weapons',
+          value: 0.15,
+          elementalTypes: ['Frost'],
+          canStack: false,
+          isActivePassively: true,
+          minStarRequirement: 0,
+          maxStarRequirement: 6,
+          elementalResonanceRequirements: ['Frost'],
+        },
+        {
+          id: 'Energy Consumption - Volt',
+          displayName: 'Energy Consumption',
+          description: '+15% volt ATK when Energy Consumption is active',
+          value: 0.15,
+          elementalTypes: ['Volt'],
+          canStack: false,
+          isActivePassively: false,
+          minStarRequirement: 0,
+          maxStarRequirement: 6,
+        },
+        {
+          id: 'Energy Consumption - Frost',
+          displayName: 'Energy Consumption',
+          description: '+5% volt ATK when Energy Consumption is active',
+          value: 0.05,
+          elementalTypes: ['Frost'],
+          canStack: false,
+          isActivePassively: false,
+          minStarRequirement: 0,
+          maxStarRequirement: 6,
+        },
+      ],
+      critRateBuffs: [],
+      normalAttacks: [],
+      dodgeAttacks: [],
+      skills: [],
+      discharge: {
+        id: 'rei-discharge',
+        displayName: 'Rei discharge [placeholder]',
+        elementalType: 'Volt',
+        type: 'discharge',
+        attackMultiplier: 0,
+        attackFlat: 0,
+        duration: 5000,
+        cooldown: 0,
+        charge: 0,
+        requirements: {
+          hasFullCharge: true,
+          notActiveWeapon: 'Rei',
+        },
+      },
+      effects: [],
+      attackBuffs: [],
+      damageBuffs: [],
+    },
     Rubilia: {
       id: 'Rubilia',
       displayName: 'Rubilia',