Enchanted Arms

As the description says, you need to Defeat the Queen of Ice at Ice Castle, which is the last level in the game.

The key thing is to say "Never!" when Toya asks you if you are ready to kill him. If you say yes you will get only the Decision achievement and the game will end. Say no, and you still have to fight Toya, but by not killing him you get to fight the Queen.

As for killing the Queen herself. First, make sure you use the healing station just before the stairs up to her. She starts out with 8000 HP and obviously is a Water Ether character. Her main attack does around 550 PP, double against Fire based characters. After you kill her the "first" time, she turns into her "true" form and you go again. This time she has 12000 HP and can do 600 - 800 PP of damage.

Try to come in with maxed EX and use your strongest Fire based attacks. Make sure you come with max (9) potions. There is a shop right there at the stairs for this. Since your TB isn't useful after this use any remaining to pick up some Skill Gems and add some more SP to your party.

I didn't find her all that tough, but I did go in with some pretty maxed lvl 60+ characters. Also bring at least one, if not two characters who have strong healing spells - but not one that is Fire Ether based - try for Water based. Someone like Karin who can heal and doesn't take as much damage.

Atsuma is your biggest damage dealer, but he'll also get pounded. Use someone like Ralgar to clear out her support so Atsuma can get a clear shot at the queen. Use the other characters to keep Atsuma alive.

Good Luck!

I highly recommend you replace Yuki with the monster Odin. He is extremely powerful and once you fight the second part of the Final Boss, he is very effective with Dark attacks.

Have Karin be the main healer. She should keep the entire party at at least 75% health. The Queen's first form is much harder than the second form.

Atsuma will deal the most damage. Raigar will be a defensive attacker. Meaning, that every few turns, he throw up Ethereal Armor for party protection. Odin will be your secondary attacker. He is not very useful at the moment except for attacking. Only use Atsuma's special attack. His do the most damage to the Queen.

And make sure to say "never" when Touma wants you to kill him or you will miss out on a 150G achievement.

Defeat the Ice Queen -
In order to fight the Ice Queen you must answer Toya with “NEVER” when he asks you if you are ready to kill him. Toya is not very hard but if you use your EX moves to beat him you will need to raise your EX all the way back up to defeat the Ice Queen. There is a VP recovery and a store right after you fight Toya so use this to restore your VP and go back to the main chamber of the Ice Castle to raise your EX back up. Before continuing up the stairs to the battle buy all the healing items you can and spend the rest of your TB on SP gems to boost your HP.

I used all 4 human characters at level 60 with direct, support and agility all maxed at 999. I also had all the moon weapons which are obtained in the Holy Beast Shrine. Each character had over 3k health. I used the EP+20%, Cut EP use, HP+20%, and the free movement supports on all characters. At this point I had done everything else in the game minus grinding out leveling and SP to boost my HP and EP. Even with my characters maxed out like this the Ice Queen was still a formidable opponent. She was even harder than the Omega Golem.

The Ice Queen has 2 forms and I found that the first form seemed extremely harder than the second. I always started with Raigar casting his 50% defense spell on everyone and Atsuma using high charge to boost his PRM by 50%. Karin was used for healing and Yuki was used for damage to The Ice Queen’s allies. I stated earlier that you need to have your EX maxed and this is because it makes the battle much easier. I died about 10 times trying to defeat her without raising my EX before the battle. Use Atsuma’s EX ability Stun Bead Fire to attack the Ice Queen. It took 2 strikes of Stun Bead Fire and a few random attacks from other party members to take her out quickly.

Once the Ice Queen has changed to her second form move Atsuma, Yuki, and Karin to the very back row with Karin in the middle. Place Raigar in front of Karin. Use Atuma’s High Charge, Karin’s Healing Spell, Yuki’s Mega Shot and Raigars 50% damage decrease spell. Once your team is in this set up do not move them just spam the Ice Queen with whatever attacks can hit her (Mega Shot, Flare Wave, etc.) from this distance and heal with Karin as needed.