You should be able to choose your warlord at the beginning. Having a team full of Chaos heroes looks weird with a guy who keeps talking about a "Divine Light"
=Tavros (Red)=
Task: Fight and don't run.
Bonus: Attack, Move, and Cast Speed are increased.
Donation: Boosts attack and spell damage for next battle.
=Vazzar (Purple)=
Task: You must choose the option the purple arrow points to.
Bonus: Your critical hits deal a random stat reduction.
Donation: A random bonus from one of the other gods.
=Azor (Yellow)=
Task: Kill the undead and use holy magic.
Bonus: Random hero gets random boost.
Donation: Boosts health for next battle.
= Nit (Black)=
Task: Kill living creatures; don't use holy magic or items.
Bonus: Increased strength and energy.
Donation: During your next battle, your heroes restore health when damaging enemies.
= Gedo (Green)=
Task: Don't attack friendly animals.
Bonus: Animals act friendly to the heroes; increased experience.
Donation: Increases your physical defense for the next battle only.
= Zoon (Blue)=
Task: Enter dens, etc.
Bonus: Reduced donation fee.
Donation: Increased dodge, block, and invisibility during next battle.
Always go back to rooms you cleared. You'll find Fiends (Purple Animals) and/or Spirits (White Ghosts). Try to kill them all! Spirits will always drop a potion (but will randomly despawn, so go for them first), while Fiends sometimes have potions. This is an easy way to regenerate health and magic.