Emilia DeSantos is what you would call a genius. An exceptional child, she graduated college at age 17 and basically became rich over night by inventing a chip that is installed into a bathroom, detecting any sign of potential illness - basically, a toilet telling its user that in ten years they might get cancer, but no worries, if they act now.
And for some obscure reason we don't know yet she became a masked vigilante called Dark Mist. One of her first exploits was a kidnapping case. A man was shot and Emilia was amongst the crowd that gathered. She saw that something was standing next to the man and now it has been taken. Because she is good at what she does she quickly found the place where the killers were hiding and took them out one by one with her powers. She then freed a young girl named Jenny who was kidnapped. The kidnappers shot her father after he brought them the ransom money and will now go to jail for that.
A bit later she heard of a bank robbery so she went in to take out the robbers. It turned out they were Redshirts and so she headed to the bank to give them a much deserved beating. She tied the gang up nicely and threw them out on the streets where the cops were already waiting. The head detective on the scene was very curious about the case and vowed to find out exactly what happened, something Emilia was not sure she liked.
After a while her crime fighting live became routine and she got overly confident, until she had a run in with somebody who was known to take down big guys. He was a street fighter and money collector for the mob. He managed to grab her and slamher into the ground, dislocating ehr left shoulder and cracking her spine. Dark Mist managed to escape when he was jumping for his gun and returned to her hideout, realizing she needed a new strategy. She developed a new suit that allowed her to project a holographic image of bats into her fog. With this new device she fought the enforcer again and this time won.
A few weeks later she finally finished her ultimate suit: and avatar body, controlerd by her mind from the comfort of a chair. This suit was completely robotic and llowed her not only to change into fog and short range teleport, it also allowed her to really transform into bats or even a wolf.