This is the front and back cover of a Comiket 47 doujin titled "ふえちすぴりっつ [Feti Spirits]" by artists from the circle RPG COMPANY, with the illustrations of both covers by a P.藤本 (P.Fujimoto), who unfortunately does not have a Danbooru entry.

極魂 is a series of doujins, with this one being one of them in the series.