I never understood why these people need to "dismiss" comrades.
If they were really concerned about him dying or something, they could have asked if he wanted to do admin duties since he had the skills for it.
Just cuz they're gonna fight a strong monster doesn't mean you have to fire your vanguard, thats why there's always a reserve army, because when you're on the backfoot it's good to have someone fresh to take the burden off. He doesn't always have to be there, but it's good to have an experienced fighter in case of emergencies.