Yoshimo would make SO much sense as a Monk. The only thing that doesn't work is that his NPC-specific equipment is a Katana, and a weapon is the last thing a Monk needs. But, a low-level Monk might need it simply for striking creatures immune to Normal weapons.

So, I created an alternate version of Yoshimo, as a Monk, using Yoshimo's original portrait--it even looks exactly like the Male Human Monk paperdoll. And now, whenever I feel that I'd rather have a Monk than a Bounty Hunter (especially considering that a Swashbuckler, Minsc, Jaheira, Imoen, and a Bounty Hunter are no match for Improved Ilyich), I simply turn down the default Yoshimo when he talks to me, and then CLUA in my own.

I don't understand why Yoshimo should be a monk. Is it due to his "Hiiii ya!" yell or his fake accent?

He's from Kara-Tur
He uses a Katana
His stats are great Monk stats
His alignment needs only a small shift (from TN to LN) to be legal
There are no Monk NPCs in the game
His entire soundset (including the ones about being in Stealth, and stupid mousetraps) is perfect for a Monk
As I said, his original portrait looks just like the paperdoll
And let's not forget that Monks are cool!

The only real thing that doesn't match is that a Monk would not have gotten on the wrong side of the Shadow Thieves, and therefore Yoshimo's existing quest would not make sense. But apart from that, it's all good.

Why would a monk use a katana?
Wouldn't it make sense for someone form Kara tur to be a ninja as well?