Hiram Grange and the Digital Eucharist (The Scandalous Misadventures of Hiram Grange)

Hiram Grange never wanted to return to Boston, where an earlier mission had gone horribly awry, but secrets from the past often refuse to stay buried. 

The Occlusionist Movement promises to expand the scope of human consciousness with their Digital Eucharist, and the wealthy and powerful are lining up to be next--unaware that there is a staggering price. Meanwhile, in the serpentine tunnels beneath the Occlusionist Tower an arch demon is freed from the Abyss, eager for revenge against the man who imprisoned it years ago--Hiram Grange! 

Cutting-edge technology mixed with ancient sorcery, undead chimpanzees, Jodie Foster zombies, and his own crushing guilt will threaten Hiram like never before. 

Good thing he still has his Webley.