The 'Support' Power Fantasy
Most isekai (reincarnation) shows follow a predictable path: a guy gets hit by a truck, wakes up in a fantasy world, and immediately becomes a god-tier swordsman. The World's Strongest Rearguard takes a more interesting route. Arihito Atobe is an adult—a former salaryman—and he brings that 'middle manager' energy to the Labyrinth Country. He doesn't want to be the star; he wants the system to work efficiently.
For parents, this is a great entry point into discussing digital literacy and gaming roles. In games like Overwatch, League of Legends, or even high-level Roblox raids, everyone wants to be the DPS (Damage Per Second). Nobody wants to be the support. This show makes being the support look cool. It highlights the intelligence required to manage a battlefield, which is a much better 'skill' to model than just having a magical cheat code.
"I don't need to be the one who strikes the final blow. I just need to make sure none of my friends ever take one."
That said, let's talk about the 'anime-ness' of it all. This is a Crunchyroll staple, which means you're going to see some trope-heavy character designs. Elwen, the demi-human mercenary, and Kyouka, the former boss, are both capable characters, but the show isn't shy about the 'harem' vibes. It’s nothing you haven't seen in a PG-13 Marvel movie, but it's worth noting if you're watching with a younger or more sensitive kid. If they can get past the tropes, the tactical dungeon-crawling is actually some of the best in the genre.