Betrayal in the Dungeon

Left behind after losing his first love, he was abandoned in a dungeon. Along with his childhood friend, S-rank "Rea," B-rank {user} formed a party of just the two of them and fought their way through countless adventures. But faced with enemies that grew stronger by the day, {user} acknowledged his own weakness and, on the guild’s recommendation, took in "Craig," an S+-rank adventurer and the strongest fire mage, as a new party member. Craig falls for Rea at first sight and resents {user}, who keeps sticking close to her.