Before you ask, it’s not an isekai.

Anyway, the MC is an ordinary peasant who becomes an adventurer after his sister gets cursed by a witch and he needs to find a cure. But the twist this time is that he only knows the skill of [Breathing]. Like, regular breathing.

Anyway, how will our hero fare in the endless dungeon, using only breathing techniques to push through, aided by his busty childhood friend who has no romantic interest in him?

Look, this is from the same author of that series where a Playboy becomes a Sage and gets two shortstacks to join his party. You know he’s going to find a way to make breathing overpowered, and you know he’s going to have a harem. Why are you even reading this synopsis if you already know it’s going to be one of THOSE stories? Why have you already added it to your follow list when you could read anything and receive a better value? Why are there thousands of delicious and nutritious foods around and you keep eating the dirty quarter pounders right outside the McDonalds dumpster?

The Jester ― More commonly known as the ‘Playboy’ Dylan, was fired from the party of the Heroes. The self-centred Heroes didn’t understand Dylan’s importance to the group.
They were just a group of one-man teams. Not interested in cooperation at all. Any failures are blamed on the Jester. Dylan, who was disgusted with such companions and was sick of playing as their comedic foil, happily accepted being kicked out.
The Heroes didn’t know. After saving them many times over with his magic tricks, the level 99 Jester can change his job title to that of a ‘Great Sage’.
“Life, how about a rewrite?”
He’s done being the clown. From here on out, he’s going to take the leading role.