Which 4* should I try to max out?

Slipshot17

I have double “Duped” Both my Thor and my night thrasher and daredevil is sig. 28 . The are all rank 3 who do I rank up

SummonerNR

Or “none of the above”. But with that roster, you could at least do Thor Rag, you will eventually get other good champs at some point and will probably have built up more Cats along the way.

Or else rankup that classic DD, he is useful in limited situations where you could use an auto-evade of certain unblockable SP attacks.