Multiple cheats!
When you are playing either a skirmish or a multiplayer, in the passcode box (press enter) type either: iamatank, iaminvincible or iamagod for different results.
Resurrect hero in Ironman mode
Normally, a death in Ironman mode is permanent. Use the following steps to resurrect your hero in v1.0 of the game. Create a backup of the saved game folder while your hero is alive. This data becomes invalid when your hero dies. When this happens, exit the game and restore your backed up saved game data. Note: This procedure involves editing a registry value; do not attempt this if you are not familiar with working with your system registry, as a mistake can cause serious problems with Windows. Start Regedit and use the "Registry/Export Registry File" menu option to create a backup copy of your original registry. Make the following changes to your registry.
[HKEY_CURRENT_USERSoftwareEnlightWarlords Battlecry III]
"LIMHK0_A"=dword:00000000
"LIMHK0_N"=dword:00000000
"LIMHK0_X"=dword:00000000
"LIMHK1_A"=dword:00000000
"LIMHK1_N"=dword:00000000
"LIMHK1_X"=dword:00000000
Start the game, and if done correctly, you will be able to select your hero again.