Onslaught vs Imperiex

One of the most powerful mutants in history, possibly the most powerful ever, vs a being as old as the universe that is full of energy from the Big Bang.

A juggernaut who had the powers of Dr. X, Magneto, and Franklin Richards vs a powerhouse with the power of the Big Bang.

Who would win?

The pale imitation of Galactus obliterates Onslaught. Spitefully.

If Onslaught has Franklin's powers, he murders Imperiex.

Onslaught wins.

Imp.

If Onslaught can use Franklin Richards powers well then he wins. Otherwise Imperiex wins.