Actually house judgment was it's own house in charge of the justice system for the fallen except that it fell apart after the great whirlwind and Variks is all that's left.

House of Judgement used to be the House of Wolves after the Queen won them over by killing their Kell, they lived peacefully amongst her ranks and were converted into a new House, House of Judgement, Judgement was dedicated to serving the Queen until Skolas came about. Variks was demotes to dreg just before every member of his house left, the Queen promoted him by giving him mechanical arms. House Judgement is now dedicated to creating peace amongst the Houses, and to Home the Kell of Kells