Sunder is one of the characters or "dateable weapons" in the game Boyfriend Dungeon (2021). No, you don't lock your boyfriend in the dungeon; instead, your boyfriend (or girlfriend) is also a weapon that you take dungeon crawling with you.
Sunder is one of the owners of the club La Rosa, along with Mandy, and transforms into a Talwar sword. The player meets him in the Verona Mall. He can be dated regardless of the player's gender.
In the game, the character is able to form a relationship with both genders and was previously in a relationship with Mandy.