Area Bosses - Which is which and how to find them

I found a Skylar from Timer, which was listed.

 Spoiler

However, after a chain of quests I failed to find any trace of Kimera, could it be that this boss isn't out yet? Or am I purely unlucky?

Nvm, I afked on that platform thinking it's not out yet... I came back and.. someone killed it too T_T

P.S: You seem to only lose 1% for dying at Kimera though.

It's based on map, not what kills you. Kimera's map is a special one and has the 1% rule in effect. Timer's does not.