The north east island with a giant tree actually got an event after beating the Fire Lord. It's pretty neat side quest, also if you are playing as a "bad" you'll encounter with an unique side quest in there.
@rpg_oldy, yeah it's weird, It shouldn't be happening lol, I thought I fixed that bug, It's probably happened in Juliet's event. Btw which version you've played in that bug? HEART.EXE
Edit: Also what was your Karma stats?
@stradar, he's a though guy to fight, he counters, heals, protects and life steals. He's not dealing much but his AOE debuff always draining your hp.