Was that truly the ending to Yoshimo's adventures with the Bhaalspawn? Is there simply no way to redeem himself or explain his actions to the PC?
Yoshimo's Remorse is a mod for BG2:ToB that makes Yoshimo a playable character in Throne of Bhaal. However, he is not what you expect him to be... So prepare yourself for some more adventures and talks with the infamous bounty hunter, a tormented soul that was left with nothing but regrets. Listen to him as this may be his last chance to find peace.