Rank up’s

manveerthereal

BestRecon

Wait for hulk 5* hulkbuster buff then choose

I would wait for hulk buster buff first, since your ghost is only a 4 star and won’t help you at all act 6 onwards.

Royalist

Rank 5 4* ghost (unawakened)

Ghost still better than Hulkbuster (post buff). Granted that she won't be of any help to you in Act 6, she will get stuff done for you in other areas of the game (Variant 3, Uncollected EQs and Elders Bane). She doesn't need the awakening just gives her more power and allows her to begin the fight phasing. If you have a ranked up Wasp then I'd say go for Ghost. Unless, you're thinking of going for Cavalier in the near future then I'd rank up Hulkbuster, but if you're planning on doing Act 5 100% first, then I'd say go for Ghost.

Kobi_Bhediya1

If you play with ghost right then only upgrade her. Else don't

Agent_X_zzz

Rank 5 4* ghost (unawakened)

Ghost she is one of the best champs in the game.