Rollicking fantasy set in modern day English village / town (in the West Country was my impression). Loki escapes eternal torment into AsgardTM computer game, and from there into self harming, anorexic teen, Jumps.
Slowly settling into their shared space, Loki and Jumps discover other gods have made similar journeys to this part of the English countryside, and soon old rivalries resurface and battles resume…
I’d not realised it was part of a series. And, yes, it is that Joanne Harris.
Author page: The Testament of Loki – Joanne M. Harris