A healer gets booted from his party because the leader notices he isn't really contributing much to the team. Soon enough, the healer must look for new members to party with. After finding a cute martial artist to work together with, he reveals his secret: while he's a fairly mediocre healer, he actually fights well in close combat. This is the story of a support who's secretly a DPS, and where the entire conflict stems from the fact that he never told his old party he was a DPS. (Source: Manga Mirai)

Despite being a healer, Raust was an adventurer that could only use elementary level heal. With such ability, Raust has trained himself to contribute even just a little to his small group of first-class party. However, Raust’s sentiment bore no fruit. In an outburst of anger because of the failed quest, the party informed him of his expulsion. However, the party members realized something little by little once Raust left the party. Raust’s ability who was training himself had put him in the realm of the top class among adventurers. It was because Raust was in their party that the party was called first-class.

https://mechacomic.jp/books/235011