I'm looking for the title of an anime I've watched several years ago (I think the anime should be from 5 to 10 years ago). I don't remember much about it, just a few scenes from the first episodes. I think it was some short anime series (12 to 26 episodes).
I remember the main character getting his power form something like a blue blob that wrapped around his arm (making it somehow looks like Chad's arm from Bleach).
There were also other people getting powers (or weapons I don't remember) in a similar way. In particular I remember a fight with an evil guy in a park who was trying to kill random people there.
The story was set up more or less in the present.