I updated the profile with his name's official reading from twitter "げぺるん". Considering his background from the first albums listed in here, it's entirely possible he's already been active in the mid 90s as "げぺるん" as a doujin composer for ActiveGamers (the earliest work I find is Imagical Musion Depot Vol.2 from as early as 1995) with the same people he collaborated on for LMCD-003 and LMCD-005.
The reason I'm even investigating is the hoot files from PC-98 RPG
Guernica, which give copyright credit to both げぺるん (GEEPEL) and げぺるん (GEPPEL) along with a real name that's probably not supposed to be public. Pure speculation, but he may have been a legit game music composer during the PC-98 era.