diff --git a/frontend/src/second-edition/components/HarcosFegyverSpec.tsx b/frontend/src/second-edition/components/HarcosFegyverSpec.tsx
index 4053dc7..ec78547 100644
--- a/frontend/src/second-edition/components/HarcosFegyverSpec.tsx
+++ b/frontend/src/second-edition/components/HarcosFegyverSpec.tsx
@@ -8,21 +8,23 @@ import {AppDispatch, RootState} from "../../store";
 import {characterSelector, setHarcosSpecialization} from "../domain-models/characterSlice";
 
 function HarcosFegyverSpecializacio(props: {
-    szint: number
+    harcosSzint: number,
+    karakterSzint: number,
 }) {
     const {
-        szint
+        harcosSzint,
+        karakterSzint,
     } = props
 
     const dispatch = useDispatch.withTypes<AppDispatch>()()
     const character = useSelector.withTypes<RootState>()(characterSelector)
-    const specialization = character.szintlepesek[szint-1].harcosFegyver || 'kard_hosszu'
+    const specialization = character.szintlepesek[karakterSzint-1]?.harcosFegyver || 'kard_hosszu'
     const existingSpecializations = character.szintlepesek.filter(x => x.harcosFegyver != null).map(x => x.harcosFegyver! as string)
-    const changeSpecialization = (specialization: string) => dispatch(setHarcosSpecialization({szint, fegyver: specialization}))
+    const changeSpecialization = (specialization: string) => dispatch(setHarcosSpecialization({szint: karakterSzint, fegyver: specialization}))
 
     const fegyver = GetFegyver(specialization)
     const availableFegyverek = AllowedFegyver(Osztaly2E.Harcos)
-    const pickableFegyverek = availableFegyverek.filter(f => f.Id === specialization || existingSpecializations.filter(x => x === f.Id).length < (szint < 9 ? 1 : 2))
+    const pickableFegyverek = availableFegyverek.filter(f => f.Id === specialization || existingSpecializations.filter(x => x === f.Id).length < (harcosSzint < 9 ? 1 : 2))
 
 
     return <>
@@ -32,7 +34,7 @@ function HarcosFegyverSpecializacio(props: {
                 fegyverek={pickableFegyverek}
                 selectedId={specialization}
                 onChange={changeSpecialization}
-                dataTestId={"harcos-specialization-" + szint}
+                dataTestId={"harcos-specialization-" + karakterSzint}
             />
             {fegyver == null && <span className='form-field-error'>Ismeretlen fegyver: {specialization}</span>}
         </div>
diff --git a/frontend/src/second-edition/components/LevelUps.test.tsx b/frontend/src/second-edition/components/LevelUps.test.tsx
new file mode 100644
index 0000000..10fd337
--- /dev/null
+++ b/frontend/src/second-edition/components/LevelUps.test.tsx
@@ -0,0 +1,69 @@
+import React from "react";
+import {fireEvent, render} from "@testing-library/react";
+import {configureStore} from "@reduxjs/toolkit";
+import {Provider} from "react-redux";
+import LevelUps from "./LevelUps";
+import userReducer from "../../shared/domain-models/userSlice";
+import characterReducer, {setCharacter} from "../domain-models/characterSlice";
+import {AllowedFegyver} from "../domain-models/allowed-fegyver";
+import {Osztaly2E} from "../domain-models/osztaly2E";
+import {ChangeOsztalyAtSzint, DefaultKarakter, Karakter2E} from "../domain-models/karakter2E";
+import {LevelUp} from "../domain-models/szintlepes";
+
+function applyLevelUp(karakter: Karakter2E): Karakter2E {
+    let next: Karakter2E | undefined;
+    LevelUp(karakter, updated => {
+        next = updated;
+    });
+    expect(next).toBeDefined();
+    return next as Karakter2E;
+}
+
+describe("LevelUps Harcos specialization indexing", () => {
+    it("updates specialization on the selected character level for multiclass", async () => {
+        const level1Tolvaj: Karakter2E = {
+            ...DefaultKarakter,
+            szint: 1,
+            szintlepesek: [{
+                osztaly: Osztaly2E.Tolvaj,
+                HProll: 6,
+            }],
+            tolvajKepzettsegek: [],
+            varazslatok: [],
+        };
+
+        const level2Auto = applyLevelUp(level1Tolvaj);
+        const karakter = ChangeOsztalyAtSzint(level2Auto, Osztaly2E.Harcos, 2);
+
+        const store = configureStore({
+            reducer: {
+                user: userReducer,
+                character2E: characterReducer,
+            },
+        });
+        store.dispatch(setCharacter(karakter));
+
+        const sut = render(
+            <Provider store={store}>
+                <LevelUps
+                    karakter={store.getState().character2E}
+                    changeKarakter={(updated) => store.dispatch(setCharacter(updated))}
+                />
+            </Provider>
+        );
+
+        const selector = await sut.findByTestId("harcos-specialization-2");
+
+        const currentSpec = karakter.szintlepesek[1]?.harcosFegyver;
+        const nextSpec = AllowedFegyver(Osztaly2E.Harcos)
+            .map(x => x.Id)
+            .find(id => id !== currentSpec);
+
+        expect(nextSpec).toBeDefined();
+        fireEvent.change(selector, {target: {value: nextSpec as string}});
+
+        const stateAfter = store.getState().character2E;
+        expect(stateAfter.szintlepesek[0]?.harcosFegyver).toBeUndefined();
+        expect(stateAfter.szintlepesek[1]?.harcosFegyver).toBe(nextSpec);
+    });
+});
diff --git a/frontend/src/second-edition/components/LevelUps.tsx b/frontend/src/second-edition/components/LevelUps.tsx
index 18330c5..16c0138 100644
--- a/frontend/src/second-edition/components/LevelUps.tsx
+++ b/frontend/src/second-edition/components/LevelUps.tsx
@@ -57,7 +57,7 @@ function LevelUp(props: {
         {szint % 4 === 0 && 
             <TulajdonsagNoveles
                 tulajdonsagok={karakter.tulajdonsagok}
-                tulajdonsagNoveles={karakter.szintlepesek[szint-1].tulajdonsagNoveles!}
+                tulajdonsagNoveles={karakter.szintlepesek[szint-1]!.tulajdonsagNoveles!}
                 changeTulajdonsagNoveles={changeTulajdonsagNoveles}
                 dataTestId={`tulajdonsag-${szint}`}
             />}
@@ -69,12 +69,13 @@ function LevelUp(props: {
         />
         {osztaly === Osztaly2E.Harcos && harcosSzint % 2 === 1 &&
             <HarcosFegyverSpecializacio
-                szint={harcosSzint}
+                harcosSzint={harcosSzint}
+                karakterSzint={szint}
             />
         }
         {osztaly === Osztaly2E.Tengeresz && kalozSzint % 3 === 0 &&
             <KalozKritikus
-                kritFegyverId={szintlepes.kalozKritikus!}
+                kritFegyverId={szintlepes!.kalozKritikus!}
                 existingKrits={karakter.szintlepesek.map(x => x.kalozKritikus)}
                 changeKrit={changeKalozKritikus}
                 szint={kalozSzint}
@@ -82,12 +83,12 @@ function LevelUp(props: {
         }
         {osztaly === Osztaly2E.Tolvaj
             && (tolvajSzint === 5 || tolvajSzint === 9)
-            && szintlepes.tolvajExtraKepzettseg != null &&
+            && szintlepes?.tolvajExtraKepzettseg != null &&
             <div className='row m-2'>
                 <label className='col-md-2 col-sm-3 col-form-label'>Extra képzettség</label>
                 <KepzettsegSelector
-                    selected={Kepzettsegek[szintlepes.tolvajExtraKepzettseg]}
-                    kepzettsegek={[Kepzettsegek[szintlepes.tolvajExtraKepzettseg], ...GetAvailableKepzettsegek(karakter)]}
+                    selected={Kepzettsegek[szintlepes!.tolvajExtraKepzettseg]}
+                    kepzettsegek={[Kepzettsegek[szintlepes!.tolvajExtraKepzettseg], ...GetAvailableKepzettsegek(karakter)]}
                     dataTestId={`tolvaj-extra-kepzettseg-${szint}`}
                     changeKepzettseg={changeExtraTolvajKepzettseg}
                 />
diff --git a/frontend/src/second-edition/domain-models/szintlepes.multiclass.test.ts b/frontend/src/second-edition/domain-models/szintlepes.multiclass.test.ts
new file mode 100644
index 0000000..5bc6d9a
--- /dev/null
+++ b/frontend/src/second-edition/domain-models/szintlepes.multiclass.test.ts
@@ -0,0 +1,60 @@
+import {ChangeOsztalyAtSzint, DefaultKarakter, Karakter2E} from "./karakter2E";
+import {Osztaly2E} from "./osztaly2E";
+import {LevelUp} from "./szintlepes";
+
+function applyLevelUp(karakter: Karakter2E): Karakter2E {
+    let next: Karakter2E | undefined;
+    LevelUp(karakter, updated => {
+        next = updated;
+    });
+    expect(next).toBeDefined();
+    return next as Karakter2E;
+}
+
+function level1Tolvaj(): Karakter2E {
+    return {
+        ...DefaultKarakter,
+        szint: 1,
+        szintlepesek: [{
+            osztaly: Osztaly2E.Tolvaj,
+            HProll: 6,
+        }],
+        tolvajKepzettsegek: [],
+        varazslatok: [],
+    };
+}
+
+describe("Harcos specialization in multiclass level-ups", () => {
+    it("adds a specialization when first Harcos level is gained at character level 2", () => {
+        const afterLevel2 = applyLevelUp(level1Tolvaj());
+        const multiclassed = ChangeOsztalyAtSzint(afterLevel2, Osztaly2E.Harcos, 2);
+
+        const secondLevel = multiclassed.szintlepesek[1];
+        expect(secondLevel?.osztaly).toBe(Osztaly2E.Harcos);
+        expect(secondLevel?.harcosFegyver).toBeDefined();
+    });
+
+    it("does not add a specialization on even Harcos class level", () => {
+        const afterLevel2 = applyLevelUp(level1Tolvaj());
+        const multiclassed = ChangeOsztalyAtSzint(afterLevel2, Osztaly2E.Harcos, 2);
+        const afterLevel3 = applyLevelUp(multiclassed);
+
+        const thirdLevel = afterLevel3.szintlepesek[2];
+        expect(thirdLevel?.osztaly).toBe(Osztaly2E.Harcos);
+        expect(thirdLevel?.harcosFegyver).toBeUndefined();
+    });
+
+    it("adds the next specialization on odd Harcos class level after multiclass", () => {
+        const afterLevel2 = applyLevelUp(level1Tolvaj());
+        const multiclassed = ChangeOsztalyAtSzint(afterLevel2, Osztaly2E.Harcos, 2);
+        const afterLevel3 = applyLevelUp(multiclassed);
+        const afterLevel4 = applyLevelUp(afterLevel3);
+
+        const firstHarcosSpec = multiclassed.szintlepesek[1]?.harcosFegyver;
+        const thirdHarcosLevelSpec = afterLevel4.szintlepesek[3]?.harcosFegyver;
+
+        expect(firstHarcosSpec).toBeDefined();
+        expect(thirdHarcosLevelSpec).toBeDefined();
+        expect(thirdHarcosLevelSpec).not.toBe(firstHarcosSpec);
+    });
+});
diff --git a/frontend/src/second-edition/pages/CreateCharacter2E.tsx b/frontend/src/second-edition/pages/CreateCharacter2E.tsx
index cd86149..8a53151 100644
--- a/frontend/src/second-edition/pages/CreateCharacter2E.tsx
+++ b/frontend/src/second-edition/pages/CreateCharacter2E.tsx
@@ -109,7 +109,7 @@ function CreateCharacter2E(props: {
                     <h4 className='col align-self-center'>Tanult</h4>
                 </div>
                 <OsztalySelector2E />
-                {karakter.szintlepesek[0].osztaly === Osztaly2E.Harcos && <HarcosFegyverSpecializacio szint={1}/>}
+                {karakter.szintlepesek[0].osztaly === Osztaly2E.Harcos && <HarcosFegyverSpecializacio harcosSzint={1} karakterSzint={1}/>}
                 <KarakterKepzettsegek />
                 <hr/>
                 {/* 1. szinten */}