Took my an hour to figure out this one and I had to reference the ORK1 wiki
A monster's EXP value is set in Development Settings in it's Combatant entry. Click the "No Status Development" box and find the EXP value box. That is NOT the enemy's EXP, but the EXP that will be rewarded when it is defeated.
Be sure to have all the other Development Settings at their correct value and that no values necessary for life are at 0 or the enemy will spawn "dead".