Although degrading, Hollander is a tough enemy. He starts by releasing a poisonous gas. He will mostly summon six Land Worms to distract the player, and although these should be easy to defeat, they can cast Gravity. Hollander will also release his deadly attack, Dimension Missile, where he brings out a giant missile from his bag and fires it to deplete around 75% of Zack's current HP, even with a high Vitality stat and Wall active. Hollander will cast either Barrier or MBarrier during the fight. Hollander normally attacks by swinging his bag.
After dodging Hollander's poison gas, Zack should cast Wall and Regen. It is important to keep Zack's HP high, and if possible, ensure he has Raise status. An attack from behind may potentially inflict 9,999 HP damage.