Welcome to MK Online kittana6.
The fake names aren't mainly because the characters want to conceal their names (story-wise it probably is) but because fighting games mainly do that and fighters have those in the real world too. Hotaru doesn't have a double life, neither does Kenshi from what I know of. The colorfulness is typical to all fighting games.
Nevertheless, Mortal Kombat strongly reminds of a superhero comic with all those colorful, masked ninjas and all the elements the fighters possess, not to mention the simple good vs. evil segregation. It's no coincidence that many MK fans like superhero comics too.
The closest we get to a masked desperado who hungers for justice is Scorpion. He is pretty brutal and wrathful though, and doesn't have a double life from what we know of (real name: Hanzo Hasashi).

Welcome to MKO.
Sit back, relax, enjoy a toaster strudel and if you have any questions, just refer to the thread above this one!
I will add you as a friend,but Im not sure you will notice because for some reason, there is no friend request system...
Hope you enjoy this site as much as I do! EDIT: link: help thread. Im not sure how long its been since anyone posted there, but I will be there if I see your post there!