For the mortals, you simply need to get to level 52 and all their abilities will unlock through leveling up. They can not learn skills from other allies or accessories, so these will unlock once you get to level 52 with everyone.

Note: Tolten only has to get to level 49.

You need to collect all the spells in the game. They can be found in chests or pots and such, bought in the stores, or learned when your mortals level up. They are also sometimes rewarded for doing minigames.

For a list of the spells click here.

WARNING: There are two missable spells during the game. They are the only two missable items in the game, so please take note of them. Shieldus and Barricadus.

You have to score 3 stars per battle set.

Here are the requirements for achieving 3 stars per set:

1. Keep Kelolon Papa and Mama alive. Cast any Water spell on them to heal them.
2. You must kill the Owl first.
3. No one in your party should go down.
4. Do not use items or magic, just melee attacks.
5. Cast All-Flara/Flarus on the enemies.

You have to score 3 stars per battle set.

Here are the requirements for achieving 3 stars per set:

1. You have to defeat their boss. Keep one Raptor alive and continue to allow it to call for help until the boss Raptor appears. Kill it.
2. Front row party members should stay alive.
3. Defeat 15 dolls first.
4. Defeat the Kelolon Brigade Leader first.
5. Do not use any Skills. Melee or magic is allowed.

You have to score 3 stars per battle set.

Here are the requirements for achieving 3 stars per set:

1. Keep everyone alive. Equip Anti-Poison and Absorb Fire on everyone for added advantage.
2. Kill the dog using Poison rings, as this is the only way to take him down. You should achieve Perfects with your hits or the skill master will do more damage. Equip Persistence on Kaim for added advantage. He can be tough, so save first since you might have to try again.
3. Hit the Moneys with fire spells or Fire-based melee attacks (or All-Flare spells). They only do coin tosses if they're hit with fire based spells or attacks, and they do not do it all the time too. You have to acquire 10 favorable coin tosses within 10 turns, and you need to defeat them within that period too. Patience and luck is required.
4. Cast Gamble on the Silver Kelolon.

After receiving all the above achievements for the DLC, you will descend one more floor and fight a very tough enemy. There is no save point down there, so if you fail you will need to run all the way back down (just turn-tail from every battle).

Now, this guide will explain how to do this battle in a mere 3-4 turns. That may seem insane for such a tough boss, but it is by far the best way to deal with him. He heals for 20k+ after every single turn, so you need to deal heavy damage quickly or he will outlast you, as he also has very big attacks on top of his auto-healing.

One thing I might suggest that the guide linked above does not, is to sacrifice one double-cast on each of your first two turns to put Reflect on all of your immortals. This will reflect away his Annihilation spell. You might also want the skill that absorbs physical damage on everyone, as this is what his other super-move deals out. Finally, you may want to try spending the turn after he casts Reflect using small spells like Flare to eat away his Reflect spell (it can only reflect 3 spells), this way you won't have to get lucky with your immortals triggering a 0-damage.

When I succeeded in killing him, I got extremely lucky (and almost everyone I've seen do this has as well) and he used a Reflect spell when he already had Reflect on himself, so this not only wasted his turn, it also triggered his third reflection. On this attempt I was using all Reversas instead of trying to eat it away with Flares, so since he broke it himself, I got in a few extra Reversas and killed him off. The battle really is based on putting as much in your favor as possible, then just hoping you get lucky.