Ordo Sinister is the fifty-sixth short story published in the Horus Heresy Series that was not originally part of a main release anthology. Ordo Sinister was first published by the Black Library in February 2017, and follows the exploits of a Psi-Titan of the Ordo Sinister.
The Webway -- a bizarre alien landscape created by the Eldar in ages long past; a network of otherworldly tunnels that burrow through time and space. When the wards protecting the Webway are accidentally breached by the Primarch Magnus the Red, hordes of daemons are able to exploit this weakness to attack the heart of Terra directly. While the Emperor Himself tries to hold the wards in place, a desperate battle takes place in the Webway -- a battle that requires very special combatants -- among them the Psi-Titan Borealis Thoon.
- Ordo Sinister (Short Story) by John French