i need help

[JagerForrester]

Did you zoom out your camera? (Part Joking, Part Serious to look for Stoners.)

You're not at max level for the fight. Check "The Naval" for its max level it syncs to, level to that and update your gear where you can. You'll have much more damage output. (You are not high enough for Darklight, which is what you referred as Twilight.)

Are you running out of TP? Look into getting Invigorate (LNC 22).

Can't kill the heart? Limit Break it.

The farther you are from Titan, the less damage you take. Your mages should be max distance from Titan at all times. Close range combat classes should find gear that increases their DEF, which sucks for MNKs.