Who would win in a fair fight; Thanos (Marvel) or Darth Vader (Star Wars)?
It's difficult to determine a clear winner in a hypothetical battle between Thanos and Darth Vader as they are both incredibly powerful characters with unique abilities.

Thanos is a powerful Marvel character who possesses superhuman strength, durability, and the ability to manipulate energy, and he is equipped with the Infinity Gauntlet, which grants him immense power and control over reality. On the other hand, Darth Vader is a skilled warrior and Sith Lord who possesses the Force, a powerful energy field that grants him telekinetic and precognitive abilities, as well as enhanced physical attributes.

In a fair fight, it would depend on a variety of factors such as the location, preparation, and strategy employed by each character. However, given Thanos' superior strength and durability, as well as his possession of the Infinity Gauntlet, he may have the advantage in a battle against Darth Vader. Nevertheless, Darth Vader's mastery of the Force and combat skills should not be underestimated, and he could potentially use his abilities to defeat Thanos if he finds a way to overcome Thanos' overwhelming power. Ultimately, it's difficult to say for certain who would win in a fair fight between these two iconic characters.