The best way to look at this is good and bad. Red is a bit more evilish? The choices are still yours but the blue choice is the more good choice. They make your Auras different colors. Depending on your Aura color, you can get different spells and skills.
If you choose to go to the red side, you will get +2 to your dark aura.
If you choose to go to the blue side, you will get +2 for your light aura.