The supporting cast in Battle Tendency is one of the worst aspects about that part though.
Caesar is a boring headstrong, hotheaded character that gets himself killed due to his pride. The two good things I can say about bubble boy are that he goes through some character growth due to his relationships with Joseph and his father (though the latter is more of a footnote compared to the former), and he has a cool death.
Lisa Lisa could have been cool, but she ends up being a generic damsel in distress because Araki was held back by higher-ups. She's not terrible but she isn't really good, either.
Smokey simply exists to give Joseph someone to look cool in front of, Anne/runaway girl ends up filling the same role for Jotaro in early Stardust Crusaders. Poco, the kid from Phantom Blood, ends up doing more than either of them.
Loggins and Messina are the equivalent of Dire, but without Dire's meme.
Suzie Q. exists to be a plot device for the ACDC fight.
Speedwagon returns to be afraid, again, but now he also serves as a plot device and a father figure for Joseph.
The one good supporting cast member is Stroheim, because Araki somehow manages to subvert expectations with that character. Other than that, the other members of the supporting cast range from "okay" to "weak at best."