This is what Andy Schmidt had to say about Marvel: The End
"Someone else answered this later, but just so you get it from me as well: MARVEL UNIVERSE: THE END is an out of continuity story, however, Thanos does refer to some "event" that seemingly bore a similar resemblence to the THE END story that occured some time in between INFINITY ABYSS and THANOS #1."
Were the Amalgam brothers the two "Gods" fighting in the DC vs Marvel books? I always presumed that it was The Presence and TOAA. Also, I'd say the strongest was the being that they made when they fused together.
When DC and Marvel stoped liking the idea of having God's so concrete looking.
Living Tribunal crushed them in while they were fighting in his pam.
But before the retcon their fight cuased a frequently destruction and reacreation of both DCU and MU.
The Living Tribunal and Spectre tried to stop them but they were beneth their notice, and blown away to oblivion, but when ther retcon took place they both (LT, S) come back and placed the Brothers in a other universe.