Reiko was once a general in Shinnok's army. He helped wage war against Shinnok's fellow elder gods. Reiko was originally from Outworld, but agreed to help Shinnok, believing he had the ability to defeat the other elder gods.
For some reason, I liked Reiko in MK4...
he was pretty much my MK4 main. I was like: "Look at this Mortal Kombat ninja who is too cool to wear a silly ninja mask!" Also, Reiko's Fatality with the throwing stars was
too good. T'was one of my favorites in the game for sure.
When Reiko finally reappeared in
Midway changed up his design quite a bit. While his new moveset was pretty boring and poorly-animated, Reiko's updated costume design in Armageddon definitely wasn't as bad as others from that game. He's one of the few redesigns in MKA who actually looks pretty decent.