JoJo's Bizarre Adventure: All-Star Battle R/Kars/Strategy
Neutral
Kars' neutral is pretty straight forward and self-explanatory, but there's still a couple basic things to go over. Your main air buttons are always j.M and j.H, with j.M being the more preferred of the two. It's fast, extremely large, leads into all BnBs and can cross up - you can honestly play neutral with just this button and be okay for the most part. On the ground, you want to use 5M and 5H for your best mids, and 2L if you need a low. Kars doesn't have any really truly oppressive lows in base form, so only sprinkle them in when you're already in the opponent's face.
In ULF, your neutral gets a little bit more complicated, but still relatively simple. Your air normals have become even better than before, and you want to transition from using j.M to j.H. Not only is the normal huge, it groundbounces on hit (leading to his best routes) and crosses up very easily. You're gonna be in the air most of the time as ULF, but remember you have access to 214X at all times whether grounded or in flight. You'll mostly be using 214L and H, but M can be used to surprise people who aren't expecting an overhead from that far. Abuse j66 when possible - it's mostly safe, gives an incredible knockdown on hit, and covers a big chunk of the screen.
Offense
Defense
Assist Usage
Muhammad Avdol
Avdol is gonna be your primary assist for ~99% of situations, since it makes teleport safe and is just generally fantastic for quality of life. However, in case you want to shake things up, here are a few alternatives:
Shigekiyo Yangu
Shigechi counters projectiles (!!!) but doesn't give much of a combo if they hit the counter to balance it out.
Guido Mista
Mista is a general quality of life and neutral assist for if you desperately need to get in. No real usage in Kars' setups, though.
Noriaki Kakyoin
Kakyoin can be used to guarantee GHA midscreen.
Jean Pierre Polnareff
Polnareff gives you universal taunt combos anywhere on screen in base form, which was something Kars never had access to beforehand.