League of Villains#
Vanguard Action Squad#
Muscular#
Mustard and Muscular have opposing views on strategic planning. Mustard believes that it's best to wait for the right time while Muscular believes that it's best to just attack now and worry about the details later.
Himiko Toga#
Mustard considers Himiko to be impractical, as he criticized her for caring more about whether or not her support gear was cute than for the equipment's functionality.[1]
Class 1-B#
Tetsutetsu Tetsutetsu#
Mustard and Tetsutetsu dislike for one another. Tetsutetsu holds a grudge against Mustard for using his Gas to hurt his classmates and for the League of Villains' invasion ruining the Quirk Training Camp. He is initially surprised that the gas villain was roughly his own age.
Mustard, on the other hand, can't stand that someone so loud and straightforward with such a basic fighting style is praised simply because of his school's reputation.[2][3]
Itsuka Kendo#
Mustard considers Itsuka and her Quirk to be exactly the kind of person and power he hates; simple and straightforward. He initially thinks of her as just another unremarkable person who's praised because of where she goes to school. He was surprised when he saw the power she could achieve with her enlarged hands.[3]