Kyouya Mitsurugi

A young man who reincarnated from Japan before Kazuma, brought by the goddess Aqua. He appears to be about high school age according to Kazuma, but his actual age is unknown. His adventurer's class is Sword Master, and he was level 37 at his first appearance. His weapon is the divine sword "Gram," a special bonus for traveling to another world. He is a handsome man with a strong sense of justice, admired by his party members, Cremia and Fio. He has a slightly narcissistic personality and behaves like a typical protagonist, always showing a dignified attitude, though he can be quite mistaken at times. Due to the power of the magic sword, he has achieved some success, such as subduing various formidable monsters like the Ancient Dragon, earning respect from many adventurers and reliance from the residents of Axel and the royal capital. When the Demon King's generals appear, the residents feel reassured by his presence. He recognizes and respects Aqua as a goddess.

Mistaking Aqua, who was in a cage for a lake purification quest, as being forced by Kazuma, he initially has a hostile relationship with Kazuma. After getting angry about the poor treatment of his party members, he confronts Kazuma, wagering the right to command him and the transfer of party members, but loses after Kazuma's surprise attack with "Steal," knocking him unconscious and taking his magic sword as spoils of victory. He later reappears before Kazuma's group, initially lashing out at Aqua with a God Blow and ending up having to pay her the reward he didn't receive. He admits his defeat and reveals he holds no grudge, demanding the return of his magic sword, only to leave upon learning it has been sold. It is not mentioned in the story, but it seems he eventually recovered his magic sword. He also appears at Kazuma's trial, where he does not blame Kazuma and even makes statements that are not disadvantageous to him, though they are dismissed by Sena.

When they meet again in the royal capital, he asks Kazuma to protect Aqua until he becomes stronger. He challenges Kazuma to a rematch, which Kazuma declines. Later, wearing his magic sword and a mask, he unknowingly fights Kazuma, who uses a combination of "Freeze" and "Create Water" to defeat him by suffocation. They meet again at a fort on the frontline fighting the Demon King's army, but they do not fight at that time.