Masamune Kido (城戸 正宗 Kido Masamune? ) is a character in the manga and anime series World Trigger. He is Border's highest person in charge. Due to his actions, he is the main antagonist of the Black Trigger Retrieval Arc.
Anime | B left
Masamune Kido has short black hair slicked back, forming a toupet in his head. He has grey eyes. He has a scar of unknown origin running down the left side of his face (right side, to the viewer). He always keeps a serious expression. Being a high-ranking member of Border, he usually wears a suit.
Kido is a serious and strict person, and dislikes anyone who breaks the rules of Border, like Osamu did. However, he was shown to be somewhat forgiving to Osamu, encouraging him to achieve his goal. Like most of his faction, he hates Neighbors and considers them enemies of the Humans. When he thinks necessary, he is willing to take extreme ways to accomplish his goals.
Kido and Yūma's relationship starts off the worst when Kido finds out Yūma is a bearer of a Black Trigger. Despite being the son of Yūgo Kuga, Kido orders Jin to eliminate Yūma, but Jin refuses with his branch leader, Rindō ordering him to capture Yūma any way he wants. Kido starts becoming more determined to get the Black Trigger, and orders several A-Rank units to go after Yūma. After being stopped by Jin, and having to accept Yūma as a member of Border, he becomes more accepting of him, promising that Yūma would not be hurt as long as he followed Border's regulations. He even allowed Yūma to use his Black Trigger during the Second Large-Scale Invasion under the condition that he didn't leave the Danger Zone.
- (About Osamu Mikumo) "People who don't abide by Borders's rules are not needed in my organization." 
- (About Masafumi Shinoda) "That mischievous brat..." 
- (To Osamu) "Work hard to reach your goals." 
- He likes his family, old movies, and black coffee.