There's a series of young adult fantasy books called Tunnels. It's set in England and features some pretty decent action sequences and a nifty story. It's got okayish setpieces, a strange amount of lore, decently written characters, interesting locations, and an obsession with the past in the "the Victorians had the best since of style and every other sense of style is wrong" with a decent helping of autism. At one point, the main characters are nearing the center of the earth (which has no gravity and is also hollow and contains national socialists? what) and get around by firing a WW2 submachine gun. This is the tip of the stupid stuff that goes on.
This is the cover of the first book.
There's fanart.
Some of it is okay.
But let's be honest, that ain't why you're here.
(This is not an OC, this is the actual main character of the series.)
(I don't even think this is original art.)
