I guess I'm doing the main four of Konosuba then.

Darkness is a high level knight in the world of Konosuba but for all her high stats her battle abilities are terrible.
But being a masochist, she takes pleasure from being beaten to the inch of her life, half the reason she joins Kazuma is his brutally honest way of speaking triggers her in a good way.
So having a tank is useful but in any other universe, she'd be dead by the end of the first dungeon.
Yes, I know, parody is part of it and at the very least she's more useful than Megumin and still hilarious to watch but I'm guessing no serious adventure groups want a death on their record which is why Darkness was never picked, bad for business and all that.