The rarity of a card can be identified by looking at the number of stars. Cards with higher rarity are usually more powerful while lower rarity cards are normally used for boosting.
|Card Rarity||Stars||Max Level|
(Base Card / Fusion)
|Common (C)||★||20||20 / NA|
|Uncommon (UC)||★★||30||25 / 100|
|Rare (R)||★★★||40||30 / 125|
|Special Rare (S Rare)||★★★★||50||35 / 150|
|Super Special Rare (SS Rare)||★★★★★||60 (70)||40 / 175|
|Ultimate Rare (U Rare)||★★★★★★||70 (80)||45 / 200|
|Legendary (Leg)||★★★★★★★||80 (110)||50 / 250|
|Ultimate Legendary (U Leg)||★★★★★★★★||90 (120)||NA / 300|
Referral reward cards ([Secret Agent] Black Widow, [Chosen One] Jean Grey, [Fundamental Forces] Invisible Woman, [Beautiful Genius Commander] Maria Hill), as well as [Extremis] Iron Man, are exceptions to the Max Level and Mastery values above.