Protect This House
Protect This House is a Halo 4 achievement added with the Champions Bundle. It is awarded when the player, in Bullseye DLC matchmaking, performs an assassination on the enemy ball carrier within five meters of the goal in a Riochet gametype. It is represented by the Gravball in front of a combat knife and a number "5" next to it.
Players can slightly increase their chances of unlocking the achievement by utilizing the Stealth support upgrade. Stealth decreases the player's movement noise and visibility to Promethean vision, but more importantly, increases the speed with which assassinations are performed, thus decreasing the odds that the player's assassination will be interrupted. Stealth is unlocked by completing the Wetwork specialization.
- The achievement's name may be a reference to the motto of the sport clothing and accessories company Under Armour.
- The name of the achievement may also be a reference to the series Red vs Blue, in which the flag-worshipping zealous "Grunts" can be heard chanting "We must protect this house!" This during what is, ostensibly, a capture the flag match, another objective gametype. 
- Xbox 360 Achievements: Halo 4 Achievements
- Red vs Blue Season 3