Thank You... Jack

Jack still had ten thousand nine hundred and seventy-six skill points. He didn't want to spend too many but Jack understood his situation. Without a powerful skill or spell to work as a finishing blow, Jack was going to fail and die. 

Some basic requirements needed to be filled by the chosen skill, such as: the attack shouldn't waste all of Jack's mana in one go, it should pair with one of Jack's bloodlines to increase its potency, there couldn't be a drawback or negative effect on the caster, and it needed to be an instantaneous attack that didn't need time to charge. These conditions helped Jack narrow his search and hasten his decision.