Azynthi Keeper is the final end-game, pre-raid boss in Erenshor, required to be killed at least 2 times to unlock access to all 4 raids currently in the game. He gave me a hard time over the weekend, but not so much as Fallen Fernalla gave me. Still, after some gear upgrades we were able to beat him quite easily!
Erenshor is a single-player RPG game that runs like a simulated MMO! My party members are not real players, but are instead bots that act like the real deal. You can interact with the "players" around the world, and do quests, dungeons, raids, etc. with them!