The cheat "Battle" allows you to fight any enemy of your choosing, at any time. Below are the correct names to use in the cheat, write it like e.g. "battle = abacor".
Cheats are not case sensitive.

abacor
Fight an Abacor.

argas
Fight Argas.

bandit
Fight a Bandit.

boar
Fight a Razor Boar.

carrionhound
Fight a Carrion Hound.

demon
Fight the Golden Demon.

dion
Fight Dion.

ghoul or ghoul1 or ghoul2
Fight a Ghoul.

gornak
Fight a Gornak.

rig
Fight a Training Rig.

spitter
Fight a Spitter.

stalker
Fight the Phantom Stalker.

thanator
Fight a Thanator.

timberwolf
Fight a Timberwolf.