*Numbers are from top down* C1 is Hidden Immortal Investigation.

>Brigadier General
(Play with and fight against)
High: E1, E2, D1
Low: D4, D7

>Crimson Lord
(Play with and fight against)
High: A2
Low: B5

>Bone Box
(Play with and fight against)
High: B4
Low: C7

>Painkiller
(Only play with (?))
High: D5
Low: N/A (If he shows up anywhere else it's so low as to not bare mentioning even here)

>Falcon
(Play with when he shows up)
High: N/A
Low: N/A

>Johnny G
(Joins automatically at the end of Rank E)
High: N/A
Low: N/A

>Drake
(Fight against)
High: C1
Low: D5

>Bishop
(Fight against)
High: D5
Low: C1

>Artist
(No clue. Can't remember)
High: N/A
Low: N/A

>Diablo
(Fight against)
High: A2
Low: C7

>Grief
(Fight Against)
High: E1, D1
Low: B1, B2

>Regret
(Fight Against)
High: E2, D1
Low: C1, C2

>Gloom
(Fight against)
High: E1, E2
Low: D2, D5

>Repear
(Fight against)
High:B5
Low: A2

>Nameless
(Fight against)
High: B1
Low: C7

>Gargantua
(Fight against)
High: C2
Low: C6

>Rogue Cinderella
(Fight against)
High: D5
Low: C5

>Klondike
(Fight against once. Fight with and take his brother, Red Dog with you)
High: B1
Low: C7

>Red Dog
(Fight against once. Fight with multiple times until he finally joins)
High: B2
Low: C2

>Sif
(Fight against)
High: C1
Low: D5

>Gun Empress
(Fight against)
High: B4
Low: B1

>Rose Queen
(Fight against)
Low: D1, B2 Good luck finding her!

>Crown Princess
(Don't attack her when she shows up as UNKNOWN in Reclaim AI-Controlled Territory)
High: n/a (D5, C5)
Low: n/a

>Savior
(Fight against)
High: B5
Low: B2

>Nemesis
(Fight against)
High: A2
Low: B2

>Abyss
(Fight against)
High: C1
Low: C2, B5

>Heaven
(Fight against)
High: C2


>Knight
(Fight against)
High: B2
Low: B4

>Deva
(Fight against with Zoa)
High: B1, B5

>Zoa
(Joins your team after the regular mission Measuring Arsenal Performance)
High: n/a (A2)
Low: n/a (C5)

>Crow
(Fight against)
High: B2
Low: C2, B5

>Notes
(Joins your team automatically after "Investigate Orbital's Territory")
Low:  (n/a) (C2, C7)

>Jack
(Fight against)
High: B2
Low: C7

>Rigid
(Fight against)
High: B4
Low: B1

>Chill
(Fight with until she joins)
High: (n/a)
Low: (n/a)

>Solomon
(Fight against maybe. Will join you when everybody else has joined you automatically)
Medium High(?): E1, E2, D1,
Low: B4, B5, A2