Kiln of the First Flame Questions

Hello. I've been thinking about the Kiln. Maybe one of you Lore Lovers can answer?

Who built the Kiln?

Was it there before Gwyn?

Did the primordial serpents build it? (they were there before gwyn and the dragons, and I don't think the
dragons built it.)

Since Gwyn was "clinging to the age of fire," was it lit before Gwyn kindled it? Or was this the place where the souls of lords were found, inside that tree in the beginning of the game?

I'm not sure it was even built, it's a location in the world. Now, as for who or what built the coliseum wherein Gwyn chills then I don't know.

Well yeah, I'm talking about the Kiln, not the land. I meant the coliseum looking thing, that acts as a kiln. For the First Flame.

Yes the kiln of the first flame is where the souls of lords were found. It could be that the Colosseum like thing was built around it by the humanoids, or it could already mysteriously be there. We don't know for sure.
So then you can wonder who did build it. It's debatable whether the primordial serpents were there before the dragons, since they are adressed as "imperfect dragons" at some point. I like to believe that they were there before though. Perhaps they had something to do with the creation of the kiln, but who knows. We can't tell for sure.