The Praxil Compliance was a war fought by the Emperor's Children during the Great Crusade.
As soon as the Imperium made contact with Praxil it was clear that whoever brought the system into compliance would gain great renown. Wanting to secure the planet's wealth intact, it was ultimately chosen that the Emperor's Children would undertake the operation supported by elements of the Imperial Army and Mechanicum under Lord Commander Iddinam.
Initially, the campaign did not begin well despite meticulous planning, with attacks on outer moons and void stations repelled with significant losses. Iddanim reassessed his enemy and planned accordingly, instead seeking to destroy the Praxil space fleet instead of waging a mass invasion. But the Praxil anticipated this move, and used multiple strike groups to attack the Imperial fleet as it gathered. Suicide teams boarded key Imperial vessels and killed command crews, while others packed with explosives launched kamikaze runs. Iddinam's fleet managed to survive, but repairs forced back his schedule significantly.
It was then that elements of the Blood Angels under Raldoron and Imperial Fists under Cazzimus arrived to aid the Emperor's Children, much to the frustration of Iddinam. Worse, Iddinam learned it had been Fulgrim himself who requested the aid. The reinforcements put themselves under Iddinam's command, but it was nonetheless a wound to his pride.
The revised plan combined both massed invasion and the destruction of the Praxil fleet. Praxil fell within three weeks of this new counteroffensive, which saw exemplary performance by all involved. Iddinam was praised for the battle, and recommended to the War Council for honoring. However before the formalities could be completed he departed the theatre, forcing Raldoron to accept the sword of the last Tyrant of Praxil. The Lord Commander is said to have never acknowledged the victory as one of his honors.
- 1: The Horus Heresy: Book One, pg. 118-119