The Atom is the latest character revealed as an upcoming DLC for NetherRealm Studios' Injustice 2. Check out this announcement video:
And before you ask, it's Ryan Choi under the mask.
"Physics prodigy Ryan Choi took on the mantle of the Atom when his mentor - and original Atom - Ray Palmer mysteriously disappeared," reads the DLC description. "Now armed with quantum shrinking technology, Ryan will use the subatomic power of the quantum bio-belt to seek out his lost friend and further the fight for justice."
A release date for the Atom DLC has not been announced.