It began in the summer of 2012 and has twelve volumes out as of October 2017.
The main staff largely remains the same but with Satoshi Tasaki coming on to work with Takahiro Yoshimatsu on the character designs.
The the first season aired as part of the 2015 summer season and comes from the light novels by author Kugane Maruyama with illustrations by so-bin that’s published by Enterbrain.