Besides Thanos who is more powerful than all of his weapons, Monkey King and Shiva can kick his ass is because they are like gods and deities. Monkey King will break Thanos's wrist and wears the gautlet to destroy him since HE TOO, have stolen armor to what he has conquered to prove his feat. The Nimbus, Wukong (Vwj Koob) has stole it from the dragons when he went into the battle. After that, he stole some armor from other places he conquered. He got so prideful to the point, he became a sore winner that the gods in the Chinese mythology, kicked him out, dumped his glory (Like what Donald Trump will say: "You're fired!"), and made him lesser than them. Wukong is a fallen god and became a demon. He became a parallel universal threat, which is beyond than Thanos. Thanos is Uno Universe, not parallel. Shiva is the same thing too; however, I don't know much about Shiva, the Indian war god.
Aries is pretty power if you go back to the original Greek Mythology. He just had sex with Wonder Woman, made his own son to kill his own mother (Wonder Woman), and then, waged a war against them for the hell of it. War is the answer to Aries's desire.