system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] Is Thanos widely considered the biggest/most powerful bad guy the avengers ever faced in the comics?
gpt
Technically, no. Because they've faced down the demon god Set, the Beyonder, the Beyonder**s**, various widescale time-travel and dimension-hopping shenanigans, the Magus (during *Infinity War*), the Goddess (*Infinity Crusade*), etc.

However, as a recurring villain, Thanos is generally remarkable in how often he *succeeds*. He collected the Infinity Gems *twice*, he willed himself to godhood with the Cosmic Cube, and it took some serious cosmic shenanigans or Squirrel Girl to defeat him each time he decided to cause trouble. It's probably to their overall relief that he eventually "reformed" and decided obtaining godhood/killing half the universe was no longer something he wanted to do--not because the Avengers were particularly good at stopping him, but because they were so *bad* at it. Generally by the time the Avengers get involved Thanos has pretty much won, or is well on his way to doing so.