Someone really wanted to implement a broken moveset.
On a serious note, the only way for him to have a broken moveset is if they pumped up the NP generation skill percentage and number of turns (those are rookie numbers), code the arts card to generate to 50% NP gauge per hit, code the quick card to generate both NP and stars on the same level as Jack's quick card, and pump the star weight of his buster card to land more crits.
Then they can code the arts and quick cards to increase hit counts for more variance in animation.