The "style" of a setter dictates how the IA is mainly gonna play, some setters play more with the WS and other's with the MB. The old styles are the following:

- Aggressive
- Arrogant
- Daring
- Defensive
- Careful
- Speed Devil (Careful)
- Speed Devil (All Speed)
- Higher & Higher
- ???

Aggressive
Aggressive styles tend to dump the ball more. You should prioritize their Attack stat.

Arrogant
Arrogant is a style which is the complete opposite of the Speed Devil (All Speed) style. 99% fours. This style is only available to the setter you have from the beginning.
Fun fact: JaeHo is also the name of one of the developers, HUNYA.

Daring
Daring is a style which the setter will prefer using quicks 65% of the time.

Defensive
Defensive is a style which the setter will prefer using the WS. Good if you usually play with WS.

Careful
Careful is a style that is very similar to defensive, but has a higher chance of giving quicks compared to the defensive style.

Speed Devil (Careful)
Speed Devil (Careful) is a style which the setter will give quicks 80% of the time. Great if you want to use MB but still sometimes let your WS do the job.

Speed Devil (All Speed)
Speed Devil (All Speed) is a style which the setter will give quicks 99% of the time. Great if you wanna kick back and let your MB do all the work.

Higher & Higher
Higher & Higher is a style where the setter will give WS. Great if you have a tall WS with strong jump and attack stats. Or maybe Nishikawa.

???
??? is a style which when the setter dumps, the setter will spike the ball unlike any other styles. The opponent AI blockers will not react to this. With maxed out attack and jump stats, a setter of this style may score better than you.

I hope you found this guide useful. Also, credits to "Crappy Cake", he's the one who made this guide originally for the OLD The Spike on steam, he really was helpful when I first started the game. Enjoy playing!