Talk:Kenkou Cross Q&A/@comment-26167729-20150304072643/@comment-12776-20150304075457

If you can read Japanese, Kenkou post detail guideline on making derivative work of MGE.

Basically...
 * You need his permission if you want to sell your derivative product.
 * If you don't plan to sell it then...
 * you can't use image from print maerials.
 * you can't use MGE for "malice" purpose (for example, hate speech).
 * He has no intention to give up copyright on MGE.

In short, if all you want is writing erotic stories based on MGE for fun, then go ahead.