E, Tamer wa Tsukaenai tte Party kara Tsuihou Shita yo ne?: Jitsu wa Sekai Yuiitsu no "Elemental Master" da to Hanmei Shita Totan ni Te no Hira o Kaesarete mo Osoi. Seirei no Oujo-sama ni Mechakucha Dekiai Sare nagara, Boku wa My Pace ni Saikyou o Mezasu node

I'm being showered with too much love from charming spirits!! I'm the only one in the world whose job is "Spirit User"!? Eren, a baggage carrier for an S-rank party, was left behind as a decoy to help them escape the dungeon because he was useless. In a desperate situation with no escape, he awakens his hidden power as a "spirit user"! He makes a contract with the legendary spirit "Phoenix" and becomes the strongest.

(Source: Kodansha, translated)