Midgard.
It was separated into the old and new parts. With the old ones being Tyr's Temple, Lake of Nine and such, however all of that was somewhat destroyed a bit during quite a few battles over the past.
Especially 20 000 years ago during the reign of 'The 10'
The new parts are as old as the 'old' parts yet they're kept up to date. All that was before is no longer in use.
Pacing there, observing it all was Satoru whom simply passed by carefree.
"Beautiful architecture" he thought to himself, climbing up inside and exploring it all, sensing someone was inside there as well.
On his right, from someone dead on the floor... A skeleton's body, covering it's mouth was a black half oni mask which he picked up.
He put the mask on.
A moment later, from behind him multiple foes surrounded him.
The darkness of the entire place made it visible that they had their abilities ready to fire.