Zense wa Kentei. Konjou Kuzu Ouji - Vol. 1 Ch. 5 - Smirk

[MangaDex]

 

[Kaarme]

He changed his decision to never touch a sword so easily that it's no wonder he still reverts back to his past life behavior when fighting. It's not like he would have had time and opportunities to develop a new battle mentality.

What comes to the enemy hero, Fai must have seen plenty of more dangerous opponents in his previous life. And he was the one left standing.

 

[WolfGunBlood-6969]

SMASH.