Get an enemy down to one hit-point then use T. Kempers attack. This attack normally only deals one damage. If you are having trouble, an easy way to do get this during the tutorial battle because you can not die during this battle. So, you can reduce the enemy's hitpoints and use T.Kempers attack more then once without the risk of being killed while waiting for the attack to recharge.
You can also try to use T. Kemper as often as possible during the course of the game. If he scores a "Critical Hit", it will deal 999 points of damage, which is enough to kill most of the enemies in a single blow, so you may get lucky.