Your best bet is to kill slime or skeletal ice mage at swordhavenundead. If your lucky you will do a critacal at least 500 on slime or 450 on ice mage.My friend once did a 697 critacal hit.
You get extremely unlucky. Killing a person is a terrible thing and should only be attempted if it is a matter of life and death. Any blow has the potential to kill someone.
you use five of your spells one is the fireball, second the whirlwind, third the tenderills of darkness, fourth froth and fifth rainbolt. hope it helps.