everybodys dying, go eat some fruit

Vash/Knives:

Twin alien brothers whose polar opposite philosophies and approaches to violence against humans do not impede their all-encompassing love for each other. Canon limb amputation and nonconsensual impregnation attempts are merely the tip of the iceberg of their deeply troubled, deeply intimate relationship.

they are twin aliens literally made for one another. they are the only two of their kind. the mangaka wanted to have nai impregnate vash but instead settled for having nai use vash to impregnate a whole bunch of their slightly less evolved sisters. it's incest all the way down with these two

Knives crashed an entire fleet of spaceships, killing millions of people, to prevent them from hurting Vash. He plans to create a “paradise” just for the two of them, so they can be together. He murders anyone and anything who opposes him, except for Vash. He cut off Vash’s arm to save his life. He even kidnaps Vash to pry open his womb-shaped gate to another dimension to “penetrate” Vash’s alien core. Vash can’t bring himself to lift a finger against Knives and cries when he realizes they’ve become too different. When he realizes he won’t persuade Vash to join his paradise, Knives annihilates himself in front of Vash. Failtwins of all time.

two blonde boys doing what blonde boys do best: look alike. theyre twins, which is hot, and they have a complicated love-hate relationship that has risked both of their lives on multiple counts! do you love mpreg? well studio orange has you covered [SPOILERS!] in Trigun Stampede (2023 Anime) with their season finale of Knives impregnating Vash with his plant tendrils! also did we mention theyre aliens who are also plants? the incest is literally out of this world; Plantcest is the best kind of incest because not only can it include Vash and Knives, but ALL of their plant sisters! fun for the whole family for millennia to cum ;))

Luke/Leia:

They're canonical telepathic magic space twins who kiss a bunch in the movies, what more could you ask for?