Nowaru

It's not possible to create a stable build. He needs to run towards the enemies in rounds 2-3 if they don't move forward themselves (and mages and archers won't). It turns out that you need to take skills in movement and invest a lot in agility, sacrificing attack and defense. And for decapitation, you need to invest a lot in willpower, otherwise, you won't have enough mana. Since accuracy is a priority, strength will be increased based on what's left (HP is already at a minimum, so let it be). As a result, mages will cast spells before he can reach them. Or, you can minimize strength, assuming that the attacks will still be deadly. Then, without mana for decapitation, it's completely useless, and he will be killed in both melee and ranged combat.

Added 1 minute ago
I was thinking about something similar, but I'm fundamentally opposed to being a samurai.