Outside the serpent entrance there was this guy Kol. I talked to him
and walked backside to the serpent temple. when I left there after awhile from main entrance, this Kol wasn´t there anymore and I heard that he has the heretic key. So what I suppose to do now? Is he still
somewhere or is he gone for good? Need help.

Welcome to the board, Jonah!!!

This bit gets a LOT of players. If you don't get the key from Kol when you first meet him, you don't get it.

Well - maybe.

If you have a save from slightly before this time, you can reload. If you were in Ishad N'ha shortly before you visited the Temple, you can revert. If neither of these is an option, you can ask Xignal or myself to hack you a key. Or you can do without it.

THe Heretic Key gives you access to a small room with a statue of Kerah and a couple of chests. Except for the anhks which can be found there, there really isn't anything that important.

Wyv