Rental Hero and Adventurer

"I will become... an adventurer!" With those words, the boy left his village. His aptitude was 'Swordsman.' After registering as an adventurer at the guild, he worked hard with his newfound companions, and finally grew strong enough that his party was promoted to C-rank on their next request. Then, during such a request, an unexpected crisis struck. And who appeared there was...! "Heyyyy, I'm a rental hero." ※The settings are pretty loose. ※High Fantasy & Comedy. (Still deciding on the genre, going with High Fantasy for now) ※The BL elements in the tags are not in the main story. If you're not comfortable with that, please skip the extras.