Bestiary boss 005 and 006 questions

[Dette]

Hi all!

Late game spoilers so proceed at your own risk.

I'm cleaning up the map before going into the elevator in the apex that says it's a point of no return.
Currently I'm trying to finish my bestiary but I'm missing two bosses, namely 005 and 006.

Online I could find that 005 is the black knight, who I have encountered three times and fought twice so far. Apparently this should be enough to unlock it, but in my case it isn't, so maybe I'm missing something? Or I misread something?

006 I could find nothing about online. Is this the final boss? Because I don't want to go to the elevator to find out it isn't when the game told me there's a point of no return.

I did find a room which seems like a boss room, with a background of three faces, but I'm pretty sure I never encountered a boss there. This room is located in the ruins of ash, left of a safe point in the middle (sort of in between the two warp points)

I have achievements for 100% map completion, 100% found secrets... So I'd say I've been pretty thorough with my search.

This is my first rogue-like and I didn't expect to love it as much as I do, great game! Really hope someone has an answer for me

[Dette]

I found the answer myself:

- 005 and 006 are both behind the elevator in the apex.
More importantly, even though the game tells you it's a last stop it's not technically a no return point, so you can go there and continue gaming after that. Would've been nice if that was clearer but hey, still love it, now going for new game+