Ragnarok

[Flying Mullet]

I don't know what 'important' stuff you can get through the Esper. Ultima could be taught by the Paladin Shield too.

http://forums.eyesonff.com/showthread.php?t=37081

Perhaps the reason why I should choose the esper is the stats it gives. Can't remember what it is though so I can't really tell the importance of it.

Ragnorak doesn't give any stat bonuses at level-up.