Author: こーすけぽけ/麻理宮ゆう/Kosuke Poke

Original:
https://kosukepoke.fanbox.cc/
http://kosukepoke.com/
https://www.pixiv.net/users/827465
https://twitter.com/Ko_Suke__poke
https://skeb.jp/@Ko_Suke__poke

Unless I've wildly missed something in the later novels, these boys aren't from Kyoukaisen. Maybe from Owari no Chronicle, but they look more like something from Touken Ranbo? When I looked on their pixiv page it seems they are original characters: https://www.pixiv.net/en/artworks/113723222

Base +3