Really though, I think FP still takes this handily. It is admittedly speculation on my part when I say this, but I believe Sise-Neg as Genesis to be even above the Living Tribunal. Why? Based on Frank Brunner's comments about Sise-Neg (Brunner was the artist for Steve Englehart for a long stretch, including the Sise-Neg arc). Here's what he has to say:
COMIC URBAN LEGEND: Frank Brunner and Steve Englehart faked a fan letter to themselves.
STATUS: True
In an interview in Comic Book Artist #6, Frank Brunner shared an interesting story about how he and Steve Englehart managed to wriggle their way out of a small controversy over a storyline in their Doctor Strange series in Marvel Premiere involving Sise-neg/Genesis, which basically revolved around Dr. Strange following “God” along as he creates the universe
Brunner:We had just completed Marvel Premiere #14-well, I had just completed the pencils, most of the art, but for some reason or another, nobody took notice of what we were doing. When the book came out, Stan finally got a hold of it, and I don’t know, somebody pointed it out, or he read it, and he wrote us a letter saying, “We can’t do God. You’re going to have to print in the letters column a retraction saying this is not ‘the’ God, this is just a god.” Steve and I said, “Oh, come on! This is the whole point of the story! If we did that retraction of God, this is meaningless!” So, Steve happened to be on his way to Texas for something, this is when we were in California, and we cooked up this plot-we wrote a letter from a Reverend Billingsley in Texas, a fictional person, saying that one of the children in his parish brought him the comic book, and he was astounded and thrilled by it, and he said, “Wow, this is the best comic book I’ve ever read.” And we signed it “Reverend so-and-so, Austin Texas”-and when Steve was in Texas, he mailed the letter so it had the proper postmark. Then, we got a phone call from Roy, and he said, “Hey, about that retraction, I’m going to send you a letter, and instead of the retraction, I want you to print this letter.” And it was our letter! We printed our letter!
Based on this, Steve Englehart envisioned Sise-Neg at the end of his journey becoming the supreme being within MU. The events in the story arc parallel Sise-Neg with the biblical God, such as when he destroys the cities of Sodom and Gomorrah and incinerates its citizens in a rain of fire, as well as creating a small paradise from the two primitive humans that he saved from Shuma-Gorath. And Brunner's comments refute anyone who tries to assert that Sise-Neg merely became a god instead of God (within MU, not TOAA level of course).