Alliance Credits can be used to buy The Joker/The Killing Joke as well as support cards that affect all characters . They can be earned in small amounts from daily log-in bonuses, by selling extra copies of The Joker/The Killing Joke (as copies can also be obtained in the Most Wanted Pack), or by referring new players through Facebook. Players get 5 Alliance credits for every player they invite into Injustice.
- The Joker/The Killing Joke - 60 Credits
- Tim Drake (+3% damage) - 10 Credits
- Ravager (+4% damage) - 20 Credits
- Starfire (+5% damage) - 30 Credits
- Talia al Ghul (+6% damage) - 40 Credits
- The Spectre (+7% damage) - 50 Credits
- Kilowog (+3% health) - 5 Credits
- Hawkman (+4% health) - 15 Credits
- Black Manta (+5% health) - 25 Credits
- Parallax (+6% health) - 35 Credits
- Swamp Thing (+7% health) - 45 Credits
It costs 275 credits to buy all support cards, and 480 credits to fully promote Killing Joke Joker solely through alliance credits.