Fantasy PvE Online Battle Game

I am developing a small-scale online battle game set in a vibrant fantasy world. The focus is strictly Player-versus-Environment, so every encounter revolves around cooperative fights against AI-driven enemies rather than competitive PvP. Gameplay should unfold from a third-person perspective, giving players a clear view of their hero, the terrain, and incoming threats.

Here is what I need help with:

• Core combat loop – responsive melee / magic attacks, enemy AI behaviors, health and loot systems.
• Third-person camera and controls that feel smooth on both mouse-keyboard and standard gamepads.
• A lightweight online layer so two to four friends can join the same session, matchmake, and tackle waves or dungeon-style scenarios together.
• Fantasy visual direction: stylized characters, spell effects, and environmental assets that instantly read as “other-worldly” without being overly realistic.
• Basic lobby, progression, and save system to track player load-outs between runs.

If you prefer Unity, Unreal, or another engine, let me know—performance and cross-platform ease are my priorities. Once we agree on the engine, I’d like an initial prototype that proves out enemy waves, co-op connectivity, and one small map; after sign-off we can expand content.

Acceptance criteria for the prototype:
1. Players can host or join a session and remain in sync for at least a ten-minute run.
2. At least three distinct enemy types with simple but differentiated AI.
3. Combat, hit feedback, and loot drops function consistently at 60 fps on a mid-range PC.
4. Source project delivered with clean, commented code and clear build instructions.

I’m happy to provide additional lore, concept sketches, and a mood board once the collaboration starts. Looking forward to seeing how you would bring this cooperative fantasy experience to life.