Onaga (with the invulnerability of the Kamidogu) vs Dark Khan
The Dragon King's powers are unaffected by the merging of the MK and DC realms, and both combatants, sorry, kombatants are capable of RAAAAAAAAGE mode. Who wins?
And just to make this match even more interesting.. Dark Khan has the ability to control the weakened kombatants who can't control the RAAAAGE within them (like Kitana, before Quan Chi freed her from Rage Mode with his sorcery), while Onaga retains his ability to revive the dead to do his bidding (this includes his Undefeatable Army and the MK characters he revived, such as Johnny Cage, Jax, and what not).