Black Summoner is an action/adventure isekai title found in the Summer 2022 lineup, and for the most part, it's a pretty conventional anime, from its medieval European-style setting and the main character's colorful party of friends to protagonist Kelvin being distinctly overpowered. Fortunately, the anime didn't write itself into a corner too soon.
Among other issues, the problem with an OP hero is that the character has too little room to grow, adapt and overcome challenges. This means that OP characters like Kelvin start their character arc at the finish line and thus have nowhere to go, so Black Summoner wisely gives a proper character arc to its side characters instead, giving fans someone more flawed to relate to.
Black Summoner's Relatable Squad of Superhero Adventurers
If Black Summoner cannot keep viewers engaged with the main character's growth and struggles, then the anime can shift that paradigm onto its side characters instead, and it works. In most stories, it's the protagonist who overcomes their flaws while completing challenges and growing as a person, from Luke Skywalker to Frodo Baggins to Son Goku. However, in anime with OP isekai heroes, that kind of character arc is more appropriate for the protagonist's friends and associates, such as the red-haired hero Toya and his three friends.
In earlier episodes of Black Summoner, fans were introduced to a squad of four other isekai heroes: Toya Kanzaki the swordsman and his allies Setsuna, Nana and Miyabi. They are would-be isekai protagonists -- ordinary high schoolers who got magically summoned to this fantasy world to fight and defend people from evil. Unlike Kelvin, Toya and his friends are more balanced and flawed in terms of combat prowess, so they have room to grow. That gives them modest but solid character arcs, and both Kelvin and viewers can cheer them on as they work hard to fight as a team and make something of themselves.
For now, in the anime, Toya's group and Kelvin have parted ways, but Black Summoner would be wise to bring them back sooner rather than later. If so, Toya and the others could show off how much they've improved as individuals and as a team. That kind of character growth is what Black Summoner urgently needs for its main cast.
Other Relatable, Flawed Heroes in Anime
Black Summoner is far from the only anime that can and should use this tactic. Plenty of other titles do the same thing, isekai or otherwise, and it nearly always turns out well. In Black Summoner itself, there is also the matter of Kelvin's knight ally Gerard, who may grow as a fighter and as a person by learning from Kelvin's example and embarking on a quest to avenge his home nation of Alcarl against the Lizea Empire. Gerard wasn't strong enough to win his previous battles, but if he works hard and grows as a hero, he may complete this personal quest after all, thus advancing his character arc.
Examples in other anime are many. In My Isekai Life, protagonist Yuji is too OP to be relatable or generate any suspense, so that falls to his charming canine companion Proud Wolf, who experienced some growth during his solo battle. This was one of the anime's most compelling fights, and for good reason. Meanwhile, the red-haired ogre swordsman Benimaru is more relatable than his OP boss Rimuru Tempest, with Benimaru having a fleshed-out character arc. He grew as a warrior and as a person in that time, truly becoming someone his little sister Shuna could look up to. It was gratifying to watch Benimaru go from a reckless, vengeful swordsman to a mature, wise and dignified leader of Rimuru's allied army in later arcs.
In non-isekai anime, this strategy works well in One-Punch Man, where Saitama has very little room for growth. Instead, this falls to his blond cyborg friend Genos who, while powerful in his own right, has ample room for improvement in his character arc. Saitama is thrilling to watch in battle, but when seinen fans need someone more relatable to cheer on, they turn to Genos. That prevents One-Punch Man from being too stale or going in circles with its ludicrously OP main character -- a lesson that Black Summoner would do well to emulate.