The third Ultros battle. Question.

Is it safe to use Relm's sketch ability on Ultros?

Yes, you are supposed to use Relm's sketch ability on him to end the battle and advance the story.

Okay, thx. What do I do to keep him busy until Relm appears? Do I have to wait or do I have to take out a certain amount of his HP?

I'm pretty sure you have to take off so many hit points. People with Bolt 2 will really help here, especially if Terra has it and you morph her first.

actually, it would also help if any of your characters had Fire2 and strago had Fire Rod equiped, along with Locke having Flame Saber. it would also help if you had at least locke and terra learn Rasp and Osmosi to drain his MP so he cant do Fire3 and Lode Stone. Then just beat the $hit outta him.

Yeah, what they said. Beat the hell out of him until Relm shows up. The above strategy works better if you Morph Terra, though.