Doro's combat power was immensely exaggerated.
Especially after the final battle with the Demon King, his strength had directly affected the "balance of the world".
Therefore, Charlette and others resorted to layer upon layer of means to weaken him repeatedly, leading to "Frodonick" attacking Doro—Doro always felt guilty towards Frodonick.
He once saved Frodonick, but he only saved Frodonick—the village where Frodonick lived had called for aid from the church, but the church couldn't arrive in time; when Doro arrived, there was only Frodonick left in the village.
Thus, Charlette was certain that Doro at that time wouldn't use his full strength against Frodonick.
Indeed, as she expected, the weakened Doro felt guilty towards Frodonick. He had one hand severed by Frodonick, and then he escaped.
So that hand was his clumsy compensation towards Frodonick.
But…
