Superman with Thor's hammer and CA's shield
In the JLA / Avengers crossover, circumstances permitted Supes to wield both mjolnir and Capt. America's shield simultaneously, but had he been allowed to keep them, who on his same level from Marvel or DC stop him with his knowledge of how to use them both perfectly with his own abilities added, and what level of being would it take to bring him down?
1. Normal mind set.
2. Enraged and bloodlusted.
No bfr.