>>714624435
Yes, beating the game with 2 Mermaid was sure a pleasant experience. Pic very related.
I only bought the game for her and I was not disappointed, her butt is divine.
>>714625871
Let another demon (preferably with phys and fire resist) take aggro and only hit him from behind.
>>714627529
Keep playing, you'll eventually unlock a case file that unlock her, you cannot miss it.
Just know that you actually unlock it early, you'll need to grind to level 66 to for Belial because you need both Nebiros and Belial for her quest.
Nebiros is a story unlock btw, you need to defeat him to unlock him for fusion but he cannot be missed.