Armor effects

Armor effects are a special customizable option in the Armory in Halo: Reach, and for Halo: Reach and Halo 4 for The Master Chief Collection. Armor effects are visible in all gametypes, though they are not displayed in cutscenes.

On November 16, 2020, when Season 4: Reclaimer was released in Halo: The Master Chief Collection, it made them available to use on the Elites. In June 23, 2021, with the release of Season 7: Elite, these effects were added into Halo 4 as a new customization option.

Death Effects
The following effect occurs when the player is killed.

Birthday Party

 * Effect: When a player dies, confetti explodes out from their body and a clip of children cheering will play. The effect is seemingly identical to the Grunt Birthday Party skull, which was first seen in Halo 2 without the cheering. The cheering sound effect would come later in Halo 3, Halo: Reach, and all subsequent games.
 * Trivia: The clip of sound is a sample from Viva Piñata for Xbox 360.

Living Effects
The following effect is continuously visible as long as the player is alive.

Legendary (Flaming Helmet)

 * Effect: Flames similar to those from Bungie Armor burn around the player's head.

Eternal

 * Effect: Similar to Flaming Helmet, but with blue flames instead of orange.

Living/Death Effects
The following effects are continuously visible as long as the player is alive, with a secondary effect when the player is killed.

Heart Attack

 * Effect: Every few seconds, a heart floats out of the player's body and disappears. When a player dies, several flying hearts will appear around the body of the player.
 * Trivia: The hearts are actually based on a temporary effect used by Bungie effects artist Steve Scott for debugging. The effect is also seen in the "Dancing Marty" Easter egg in Halo 3: ODST.
 * Note: This armor effect has the potential to kill enemies in both firefight and matchmaking according to the Bungie.net heatmaps.

Pestilence

 * Effect: Bugs and a cloud of green flows around the player. When hit, instead of blood, the player bleeds a green liquid similar to the pus-like fluid which is seen when shooting Flood forms. Upon the player's death, he/she explodes in a manner similar to a Flood carrier form. Occasionally the cloud will be red instead of green.

Inclement Weather

 * Effect: Electricity and thunderclouds swirl around the player's body. Upon the player's death, a bolt of lightning strikes its body.
 * Trivia: This Armor effect's name is possibly a reference to Cortana's comment on Halo's climate as heard on Halo: Combat Evolved campaign level Assault on the Control Room; "Interesting... the weather patterns here seem natural, not artificial. I wonder if the ring's environment systems are malfunctioning... or if the designers wanted the installation to have inclement weather."