Who said "Death is merely transition. A door, not an ending."?

This quote is attributed to Tiamut.

Death is merely transition. A door, not an ending. - Tiamut

"Death is merely transition. A door, not an ending."

Tiamut Death

"I am inevitable. I am eternal. I am Tiamut."

"Your species has had its chance to evolve. Now it is time for change."

"Life and death are but moments in an endless cycle."

"I have witnessed civilizations rise and fall like leaves in the wind."

"Death doesn't scare me anymore."

"Death and I are old friends."

"Welcome to my world."

"Death is just the beginning."