Ano Toki Tasukete Itadaita Monster Musume desu. - Ch. 3

[ExecutiveDirector]

Really rubs me the wrong way how he was a powerful hero that's so weak now. Has he just degraded with age and lack of practice with magic, or does he have some trauma with his power? I guess he also hasn't had any reason to use it so is just another secretly strong character thats going to wow everyone around him once he reveals it. Either way I hope he snaps out of his meekness soon

Nothing in the story said anything about him being powerfully at all. It explicitly says he let the summoners down.