Defeating Myria can be difficult task if unprepared or underleveled. During the first half of the fight, the biggest obstacle is dealing with Myria's status inflictions through Venom (confuse, poison, blind) and Evil Eye (paralysis). Equipments and accessories that helps resists status change are extremely helpful- Holy Robe, Silver Tiara, Mist Armor, Diana's Dress, Protectors, Light Bangle, Ivory Charm, etc. Don't focus too much on buffs as Myria's Sanctuary will nullify them. Throughout the fight, Myria will use a plethora of high-tier elemental spells so equipments that raises elemental resistance (Dragon gears, Sun Mask, Ivory Charm, and etc) will help lower the damage. Utilizing elemental rings (steal/pilfer from the Ice and Fire Drakes to acquire addional Ring of Ice and Fire) is an effective way in nullifiying the damage. Be wary when using Ascension as it will alter your resistance properties. Once Myria loses half her HP, she will stop using Sanctuary, and gain access to Mjollnir and the devastating Holocaust. The buffs should be safe, as she will not nullify them. Holocaust will chip away a large chunk of HP, so be prepare to heal. Once Myria is down to 1/4 of her HP, she will use Venom and Holocaust very often. Momo is helpful in this fight as she has access to Vitalize and Raise Dead, with sufficient AP to use them multiple times. Also, her high INT means she will take less damage from Myria's magical attacks, and she is able to wear the most of the top-tier status resistance equipments. She can also assists with buffs or deal heavy damage if you give her Shadowalk. If you opt to not bring Momo and have Ryu use Ascension, make sure to carry a large supply of multi-healing items such as Whales, Spearfish, or Vitamins. Rei is also a great character to use as he can easily outspeed Myria (naturally or through usage of Speed), and support the party through item usage or dish out heavy damage via Weretiger or abilities such as shadowalk, triple blow, or Aura. If you need extra speed, stealing a Burglar's Garb from the Vampires will help boost Rei's speed. Nina can also easily outspeed Myria (given the right equipments/ buffs), and with her high AP, can support the party via buffs such as War Shout, Barrier, and/or Cure Shield (learn from Meryleep, Emitai, Ygdrassil, and via examination at the Drake in the desert respectively). However, keep in mind that both Nina and Rei suffer from low HP and Def, so keep an eye out for their health if planning to use either of them. Ryu can function as a support or tranform, through preferably the latter. Tranforming into Warrior or Myrmidon and use focus/Aura will deal major damage to Myria. If using Warrior, add a flame gene as Myria does tend to use Sirocco and Inferno. Watch as for your AP and carry extra Wisdom Seed/Fruit or Black Porgy. Avoid using solo dragons (Behemoth, Mammoth, etc) as if paralyze by Myria's Evil Eye, you will be a sitting duck until you run out of HP or all your AP is drained out.