Bowser (2012)

Bowser, the Avenger, was once a very close ally to Thanos, and was one of the main antagonists of the 2012 film Avengers along with Shigaraki. The old Bowser briefly appears as an antagonist in Avengers: Endgame.

Appearance
He is the same person as Bowser, and looks the same. For Bowser's description, click here.

Story
"Evil Bowser" first appears during Act II when the Avengers attempt to get the Reality, Space, and Mind stones from Fourside in 2012, during the events of the first Avengers film. He attacks and kidnaps Nia, Shulk, Paula, Patrick, Hopadiah Plantar, and Squidward. Bowser then re-appears in the Memory Chamber with Thanos and several other villains to search through Aqua's memories of Infinity Stones in the future. Here he is shown to be very impatient, as he quickly becomes annoyed with Squilliam and Himiko Toga toying with Aqua and asking irrelevent questions. Past-Bowser is killed by Shulk at the end of the nomu gauntlet hallway.