hello there mate,

first of all, congratulations obtaining one very good and very op unit.

secondly, my advice for you is making him 4 stars as soon as you can. because very soon he will get his skill trials.

as for your question, for us to help you more, you should tell us, for which PvP event you need help.

as you already know, different units are considered and react better in different PvP events.

in my opinion there are a lot of units that you can try, supporting him very good, such as Izuna (his brother), Jiraiya toads chant, Shisui all of his versions ( maybe not kimono 4*), Danzo Ianag full sbi or his seasonal version or his first version full sb, Hiruzen 3rd Hokage 4* full sb,

of course there other units that can work more for your defensive mode, such as Indra * full sb.

the best unit that work best for him is Sasuke SS

i would love a completely Uchiha team, Sasuke SS, Madara FB and Izuna. they are all sword type units, but i dont care :)

i forgot to mention about Hashirama FB or his edo version full sb that both can work very good also.

whiskey in the jar :)

I also advice checking out the official discord for fast strat help (as mentioned in the strat pinned post, forum won't cover as much):

Madara isn't benefiting from Masked Man or Itachi as supports. Recommend helping him out with chase increase (Hashi New Year, most if not all players have him) or Asura breakthrough if you have him. Additionally, while chakra battery isn't needed, nice control / chakra gain is Jiraiya Toads Chant (as mentioned by another).

Shisui Modern Asian style can be an okay support but don't recommend most other Shisui forms as they're outdated or would be a "better" position 1 / damager (like Shisui Susano'o four star breakthrough outclassing Madara himself).

Thanks for the advice, it's a really strong team. If you have any other advice, I'd be happy.