The FAQ section in the walkthrough explains all raid bosses and their abilities. Keeping her MP below 500 makes the fight a lot easier.
Her DEF and M.DEF is equally strong. Her max MP is 600. Keeping her MP below 500 will prevent her from using her Curse spells.
Skills:
Steal Energy: Steals 90% MP of all enemies.
Ancient Curse of Death: Requires 500 MP. Does max HP –1 as damage to one enemy, so every character below 100% will die instantly from this spell.
Ancient Curse of Pain: Requires 500 MP. Does 75% max HP damage to all enemies.
Nature's Reclaim: Strong life leech against one enemy.
Plant Bite: Physical attack