Unreal Engine 5.6 AI Tutorial #21 (Sep 2025) Katana Combo System with GAS & Multiplayer Replication

UE5 Melee Combo System Tutorial | Continuous Katana Combos with Gameplay Ability System (Multiplayer Ready)

Welcome to this Unreal Engine 5 (UE5) melee combat tutorial! 🎮 In this video, we dive deep into creating a continuous combo system for melee combat using the Gameplay Ability System (GAS). Our focus will be on katana combat mechanics—teaching your character how to chain attacks seamlessly, maintain combos, and replicate everything properly for multiplayer.

This tutorial is beginner-friendly but detailed enough for advanced UE5 developers who want to implement a polished melee combat system in their action RPG or hack-and-slash project.

🔥 Step-by-Step Implementation
1. Understanding the Problem

Normally, melee attacks reset after one swing, leaving no sense of flow.

We want to create a continuous combo system, where if a player presses attack again before the first swing finishes, the next swing naturally continues (e.g., Attack Right ➝ Attack Left).

This makes the combat feel smooth, stylish, and responsive.

2. Setting Up Anim Notify States

We create Anim Notify States to mark windows in attack animations where follow-up attacks can trigger.

Example: If the katana swings from Attack Right, the notify marks the point where an Attack Left backswing can begin.

Why? → This ensures combos only flow when animations visually allow them, maintaining realism.

Steps:

Create a new Anim Notify State.

Name it ANS_AttackLeft (for swings that must start from the left side).

Place the notify in the attack animation timeline where combo chaining is allowed.

3. Adding an Attack State Enumeration

To track which side the weapon is currently on, we add an Enum called E_AttackState.

For now, include: AttackRight and AttackLeft. (Later, you can expand with Up and Down).

Why? → This gives the system context to decide which next attack animation should play.

4. Updating the Character Blueprint

Add functions via the Weapon Wielder Interface:

SetAttackState(E_AttackState) → Updates whether the katana is currently at AttackRight or AttackLeft.

GetAttackState() → Returns the current state for decision-making.

Default the state to AttackRight (katana starts in right-hand position).

5. Integrating with the Gameplay Ability System (GAS)

In your katana light attack ability:

Instead of randomly choosing animations, use the AttackState to decide.

If the katana is on AttackLeft, the next attack must be an Attack Left ➝ Attack Right backswing to maintain a natural combo.

If the katana is on AttackRight, multiple attack options (horizontal, diagonal, vertical slash) are allowed.

This creates logical combo flow.

6. Notify State Logic (Begin & End)

In NotifyBegin: Call SetAttackState(AttackLeft) (because this is ANS_AttackLeft).

In NotifyEnd: Reset to default (AttackRight), meaning combo window is closed.

Why? → Prevents attacks from chaining unrealistically outside the allowed window.

7. Gameplay Effect for Attack Lockout

Use a Gameplay Effect to temporarily block re-attacks (e.g., 1 second duration).

Once the attack animation ends, remove the effect so the next attack can trigger.

Why? → Prevents button-spamming and ensures timing-based combos.

8. Testing Combos

Test in single-player:

Press attack at proper timing to see continuous combos (AttackRight ➝ AttackLeft ➝ AttackRight).

Wait too long and the combo will reset.

Test in multiplayer (client + server) to confirm replication works with GAS.

Result: Both client and server see synced, fluid katana combos.

✅ Summary of the Process

Anim Notify States (ANS_AttackLeft) mark valid combo windows.

E_AttackState Enum tracks the katana’s current position (AttackLeft or AttackRight).

Character Blueprint & GAS decide the next attack logically.

Gameplay Effects ensure proper timing and prevent spam.

Works in multiplayer with full replication thanks to GAS integration.

This gives you a stylish, responsive melee combat system with natural katana swings that feel impactful.


Unreal Engine 5, UE5, gameplay ability system, GAS, melee combat system, katana combat tutorial, UE5 melee combat, combo system, blocking system, continuous combos, multiplayer melee tutorial, Unreal Engine action RPG, hack and slash UE5.

🎥 If you found this helpful, check out the full playlist of my UE5 Action RPG with Gameplay Ability System tutorials. Each episode builds on the last, helping you create a professional-quality combat system step by step.

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