So like about a dead god tier body from an alternate time line and a dream self would fuse them together when the player dies right??? So you would go double god tier or what? Godtier^2??

You can’t Ascend if you’re already a God Tier, regardless of the conditions. Only way you can achieve more than your God Tier is prototyping yourself with another God Tier, in which case it’s not God Tier^2, rather, just. Two titles in one.