How Four Negative Skills = Unrivaled Synergy

Overview

Alvin is a young adventurer with an atrocious negative skill. In spite of his overwhelming strength, he's considered a nuisance by those around him and kicked out of his party. In the throes of despair, he hears a rumor about a dungeon where one can obtain an item that erases skills and recklessly decides to solo the boss. That is, until he meets Cocoru, a cleric who has also long suffered from her own negative skill. However, when Alvin learns the effect of her skill, he can't help but think… "Couldn't our skills work well together?" The negatives cancel each other out and become a positive! As their skills multiply together, nothing can stand in their way! This is the ultimate "mutual support" story for these unfortunate adventurers! (Source: Manga UP!)

Source: AniList