All these characters was done for eSteem.app mobile and desktop client for STEEM blockchain blogging platform. It started as my personal project. I wanted to contribute into eSteem application to support things I like. Gradually it became commercially successfull with the help of Steem vote system. I haven't sold anything but it got payed. Could you imagine that? I've just created some daily art posts on steemit.com and started to get money out of it.