To add max health, mana, control.
It's easiest to edit the small sav*.cpn files under the "savedgames" directory.
The small ones are the ones you auto-saved between campaigns.
(Sort them by date-modified if you're unsure which you saved last.)
After getting his first spells, Aurax becomes a wizard and can be edited.
The first game as the magic-using Aurex will usually put his stats in the 0x800 region like this:
0x87E-0x87F [C8] (normal max=[E8]=1000) Health
0x880-0x889  Unknown
0x88A-0x88B [3C] (normal max==400) Mana
0x88E-0x88F [0A] (normal max==40) Control
The game will shift the location further down as the game progresses, so just search for the string "aurax"
Savegames from within a mission will have several "aurax" strings.
One of these will store his normal maximums (same format as above.)
One of these will store his current status in the mission.
It stores current health 18 bytes after that "aurax" string.
Current mana is linked elsewhere.
Yes, values beyond the normal max is legal, but overdoing it spoils an already-easy game.
During a multiplayer game you can explore the area without leaving the mana spot. All you do is get onto a mana spot and summon a dragon and all the phoenixes you can summon. Leave the dragon near you as a guard and send the phoenixes off to fine other mana points. So...say is you find 5 mana spots and put phoenixes on them you get 5x more recharge than you normally would.