I can't recall off-hand if Deathstroke has appeared in the Injustice comic or not before now. In either case, his appearance here is well handled and - much like the earlier appearances of Green Arrow and Harley Quinn - reflects the character as he was before The New 52. This is the principled mercenary Slade Wilson as written by Marv Wolfman and Brian Buccellato does a fine job capturing that voice.
Mike. S. Miller does an equally fantastic job on the artwork. The artwork for this series has rarely been anything worse than average but I believe Miller is probably my favorite of all the many fine artists to work on Injustice. He has a great eye for detail and always finds the perfect balance between merely outlining the original pencils and enhancing them. Talking of enhancements, the color art by J. Nanjan is impressive.