Which mutant to rank 5?

Klerr

Since these 3 mutants are all unawakened, which one should I use a mutant awakening gem on? I heard that Domino is good for act 6 (spam heavies), but apparently Colossus is good as well. In addition, Colossus is a viable LoL candidate?

Fluffy_paws

Domino is a good option to rank but don't use a gem on her, her awakened ability is defensive.
If you run suicides go for OR

FeroX_the_fat_hering

5* r1 unawakened Domino (I have both 5* Massacre and 5* Red Hulk)

Yeah Domino doesn’t need to be awakened. She is insane with rhulk and mas, but she is still very good without them. Most of the time I use her without the trinity

doctorb

5* r1 unawakened Domino (I have both 5* Massacre and 5* Red Hulk)

OR is good if awakened and max sig. Otherwise go for Domino. She's great as is, especially with the other 2. Just learn how to use her well.

SpideyFunko

5* r1 unawakened Domino (I have both 5* Massacre and 5* Red Hulk)

use the gem on Colossus, or Omega if you can get him to max sig. rank up Domino, or colossus if you can awaken him, and Omega if you can get him to max sig

Qfury

5* r1 unawakened Domino (I have both 5* Massacre and 5* Red Hulk)

Domino solely because the other 2 are unduped and they kinda need it. Domino doesn't need it unless you wanna stick her on D

Thanks_D19

5* r1 unawakened Domino (I have both 5* Massacre and 5* Red Hulk)

Colossus and omega red both need dupe and pretty high sig

King_Leo321

5* r1 unawakened Domino (I have both 5* Massacre and 5* Red Hulk)

Wait for colossus to get awake.

Aleor

5* r1 unawakened Domino (I have both 5* Massacre and 5* Red Hulk)

Gem for Colossus, r5 domino

lowlevelplayer

5* r4 unawakened Colossus (I have 5* Omega Red but no 5* Emma Frost)

if you have 199 sig stones, max out omega. If not, both domino and colossus are great. If you plan to do LOL, colossus is probably better