Maliris frequently uses Fire magic on the party and especially with her sword attacks. Maliris also likes to cast Mustard Bomb on the party, which inflicts the Heat status. Quina can learn this technique, but not from her. She casts Reflect on herself and will reflect Fire spells off herself to hit the party. When defeated, Maliris attacks with Raining Swords that will do about 4000 HP to all characters.
If the party has Auto-Reflect, the player doesn't need to Dispel Maliris's Reflect status, merely reflect Blizzaga or Water off a character, or the whole party for a stronger effect. Zidane should steals all the items Maliris has, as they are hard to find elsewhere.
Most of the party should have their HP almost fully healed by the end of the battle to survive Maliris's Raining Swords attack, although it is recommendeded at least one of the player characters has Auto-Life.
The translucent form of Maliris is considerably weaker, as she does not perform Raining Swords upon her defeat and has a substantially lesser amount of HP. A constant barrage of Ice-elemental magic and physical attacks charged with the Devil Killer ability should be enough to bring this snake down quickly. Crystal Maliris doesn't give EXP.