Sorry, don't mean to spam here, but I'm waiting for some paint to dry so I have time!
The main theme of the FF-Kahdi leaves the Amurites. From there we can go.
Good Leader: Feels stifled by the Amurites and perhaps feels they don't see the dangers of Erebus that he can save them from. (Again the Good leader seems to beg to have the arrogant/prideful problem). Angel shows up and says, "You're right to see the danger and I can help you. Go forth and found your own people and you can be the Savior!" So off s/he goes.
Neutral Leader: Similar to the above, but if we go with the idea I put forth in the above post, perhaps in his search for 'ultimate knowledge' he goes past ethical limits. He's not evil, he just totally either doesn't think about the moral issues or just believes that the greater good requires some sacrifices. Not a 'mad' scientist but just one that is dedicated to the quest. The Amurites, however, don't take kindly to his experiments and boot him. Up shows the Angel and gives him the pitch. So off s/he goes.
Evil Leader: Feels the Amurite leadership is failing to fully step-up to the example of Kyrollin (sp) and feels that unless 'some omelettes are broken to make eggs' the Amurites will fall. The Amurite council disagrees and banish him after a failed coup attempt or something. Up pops the Angel saying, "They don't understand what needs to be done to save your people. Only you can save them...but not here. I will help you." So off s/he goes.
So what happens is the leader goes off and finds this remote group of people that survived the Age of Winter/Ice through their connection to of the divine in everything (kami) which they get through intense study, meditation, and a physical regime.
The Good leader will be like, "Great! A people steeped in magic, lore and duty! I couldn't ask for better!"
The Neutral leader will be like, "Great! A people in tune with knowledge as well as a path not taken by the others. What a great opportunity to learn!"
The Evil Leader will be like, "Great! A people who understand disciple and duty and who push themselves to achieve that goal! With me as their leader, I will save all of Erebus."
So to me, the Good leader wants to gain magical knowledge and build up his people because he feels that they will be the bulwark against evil and that 'shining city on the hill' that will light the way. I'm thinking that this leader would be something like Charismatic/Creative. For mana, Body, Earth, Life.
The Neutral leader mostly wants to be left alone to further the pursuit of knowledge but will aggressively pursue what he desires for his studies (like mana nodes or unique sites that provide mana). I'm thinking Philosophical/Defender with Mind, Nature and Enchantment for mana.
The Evil Leader wants to bring Order to Chaos and feels that only S/He can do it so will do it by force if needed. Perhaps Expansive/Charismatic with Spirit, Fire, Law