Question: what is the most powerful weapon in the universe?
Answer: Infinity Gauntlet. As the main focus of Avengers: Infinity War, worn by the mad Titan Thanos, this is definitely one of the most powerful weapons in the Marvel Universe. ... 
Mjölnir. ... 
Captain America's Shield. ... 
Cosmic Cube. ... 
The Crimson Gem of Cyttorak. ... 
The Darkhold. ... 
Nega-Bands. ... 
Universal Weapon.