Nightmare of Mensis help

I assume you're talking about Micolash, right?

If you really can't stand him, there is a cheese you can pull off. Chase him around until you fight him in that room with the two skeletons, then after he disappears chase him again.

When you get him in front of the room with the broken ledge he drops off into( the one where if you drop off after him, he runs into the next room and the barrier comes down)

Do NOT drop into the ledge, but stay at the top where you can just barely lock onto him. From here, you can hit him with whatever projectiles you have. I recommend poison knives, as 3 knives should get him poisoned for a while. If you have simons bowblade even better; just shoot him to death.

Loch Shield helps with this fight, if you have the DLC.

Thank you everyone he is dead.