Frost
[ A/N: This chapter will contain detailed explanation, so if something goes over your head just skip it, you just need to understand the final result of the skill. ]
Therefore he decided to work on Andrea and Genis later, he couldn't do anything about them right now anyway.
Then he came to one of his most useful skills, Void eye, there wasn't much he could do directly, since he didn't have many ways to use his mental abilities, and he had one skill related to soul attack and one to mental.
[ Soul eye and Cursed Voice ]
But he focussed on the Spatial property of his Void eye skill, he thought of various ways to use it and then the thought of using it to Freeze the enemy came to his mind.
Even freezing the opponent for an instant during battle would be detrimental, so he began to think of ways to make it possible.