The House of War is one of the three great houses that make up the governing body of the Drakon Empire. Formerly ruled by Emperor Ko-Dorr, the House of War's primary responsibility to the empire is the building and commanding of the empire's police and military forces. They organize all of the Drakons' military campaigns and spearhead the invasion and conquest of other worlds.
Although unconfirmed, it is likely that the House of War orchestrated the retrieval of the Chaos Emeralds in Mobius' ancient past that led to the Great War between Drakon and echidna forces. The Drakons were eventually defeated and retreated to their own planet. For the next few thousands of years, the House of War would turn their attentions to seizing planets by other means.
In the present day, it became apparent that Mobius had become a technological threat when Doctor Ivo Robotnik began communicating with Drak through a Mobius Ring. The House of War]] sent a Prosecutor through the Ring to seize whoever was responsible, eventually choosing Robotnik to be punished. However, his knowledge of the Chaos Emeralds convinced Ko-Dorr to strike a deal with him and the pair pooled their resources together and captured Sonic the Hedgehog.
Sonic was placed on trial in Robotnik's place and subjected to Trial By Combat against a Metallix Mark 3. Tails was able to track them down and ended the fight by opening the door to the Arena of Judgement and destroying the Metallix with it. Robotnik tried to use the Prosecutors to kill Sonic, but Ko-Dorr stuck to the letter of the law and allowed the Mobians to go.
Even so, Robotnik and Ko-Dorr's deal continued and the Mobian ex-dictator vowed to help the House of War find the Chaos Emeralds. The faction desperately wanted the gems for themselves, going as far as to lie to the House of Magic and the House of Knowledge about their involvement with Sonic. After Grimer "betrayed" Robotnik, he led the House of War to the Floating Island and the Chaos Emeralds, culminating in a fierce battle with Sonic and the Guardian Robots. Grimer soon showed his true colours, using his Dimensional Staff to teleport the Prosecutors and Sentinels to an unknown location, likely decimating Ko-Dorr's forces.
Many years in the future, Sonic arrived on Drak to make a deal with Ko-Dorr, only to find that he had been deposed and replaced by Emperor Brokken. Instead of talking with him, he held a meeting with Sister Haggra and Master Scholar, suggesting that the House of War was no longer on parity with the other two major houses.
Sure enough, when Blaze the Cat found herself transported to Drak by The Order of Magick, renegade Etsu revealed that the House of War were now puppets of the House of Magic and that Haggra had control over the Prosecutors and Sentinels.