Next rank 4 5*

Kjproness

Who should I get to rank 4 next
All have no sig

solopolo

I'd go for Medusa. You already have Iceman so Killmonger would be a bit redundant, and since you only have 1 r4 so far I wouldn't rank up defenders just yet, otherwise Korg and Morningstar are also good options, don't know if Korg needs to be awakened though.