The villain focused comics are going to be called Fiendship Is Magic (I see what you did there) and will be released throughout the month of April.
Here's the synopsis for each issues. Although they're not really much of anything other than "find out how character x started." So nothing really spoilery, except for the last one, that one is actually pretty interesting.
2 - Tirek - Tirek's mad quest for power starts here!
3 - The Sirens from Rainbow Rocks Equestria origin revealed!
4 - Nightmare Moon - The untold story of what Nightmare Moon did during her time on the moon!
5 - Chrysalis - The ponies visit the imprisoned Chrysalis... what secrets is she hiding! (Something other than a origin story, and actual continuing story? Now that's more like it.)