"Yes. I am no longer, Sahashi Tsubasa. He was nothing but a coward. I am duke Stefan De Arno. Commander of the Dawn Bringer. I am no coward. The dawn I wish to see is the light of my enemy's corpses on fire."
As if that was not enough, his body and identity the only thing connection to his family was stolen by Bifrons. And in his desperation, he offered up the Archdemon to me on a silver platter just so he could get his vengeance.
He then took a chance and transferred his mind into this chimera. Unfortunately, even his gamble turned out into a dud. Leading to the current result. Even though he followed the template of a standard Isekai he didn't get to achieve the ending most stories in the genre got.
Of course, from my point of view he was the main reason for his failures. If he fought on the front lines, he might have gotten strong enough to protect those he treasured. But alas, we must live with the consequences of our mistakes.