This fight is doable about 24ish (now done it twice).
If you're around that level you won't be able to keep everyone alive, don't try. Your strategy is basically this: run around as Oliver, stay away from the boss, use Fireball when you can, and grab blue glims every chance you get. You MUST use Defend on Bolt from the Blue, so be ready for it - don't rush to try to get in multiple fireballs since that can leave you open. Gold glims will help shorten the fight with Burning Heart. Do NOT attack the
that appear at 25% health. Just continue running away and fireballing when you have the MP for it.
After this, I highly, highly recommend following the level up strategy I posted above. Killing 14 tokos (and the assorted trash kills you'll get) is the difference between painful 10 minute boss fights and facerolling.