*Please note: this show is not about the food Onigiri. I'm sorry :P
The description of the MMORPG goes something like this:
Onigiri thrusts its players into mystical Japan, a land filled with mythical creatures of Japanese legend. Starting as a lone Oni, players fight against the malevolent influence of the Kamikui as their miasma spreads over the land. 8 NPCS, each with their own distinct personality and skills, ally themselves with the player to help build a legend, and quell the evil that has arisen. As you grow stronger together, so do the bonds binding you to each other.
Apparently, the game sort of inspired by / teaches Japanese Folklore, so that's kind of cool, too.
It's not clear yet what direction the anime will take that story (will it be a male MC? Female? Harem anime? Not? What's the story?!) It looks kind of like the main character is female, with 3 male NPC's and 5 female NPCs? But who knows! I haven't played the game myself, but I heard the the setting is pretty fantastic, so it might make for a good anime!
I found this video introducing the game, so we can expect that the characters will be similar ones, so you can get to know them a bit now!