King Koopa and Princess Peach are in "LOVE", the kind of we really like to fuck together and now we can't live without one another love, but sadly for them, King and Queen Toadstool (don't know if they actually exist but they do here for the sake of the story XD) don't see Bowser very well and are against interspecies relationships (raciiiists buuuuh). Peach came up with a plan, she'd get kidnapped by Bowser to spend time together and call a fake saviour for "help" after some time, building a relationship with him destined to have no possibility of a future together... all to trick her parents and take that big fat cock down her throath. He was initially against the idea of getting beaten just to have some time alone with her but time passed and the Koopa king, tired of masturbating using only koopa shells and random sluts, decided to assault the castle... and take what was rightfully his property.