The Type-1 Energy Weapon, better known as the Energy Sword is a melee weapon found in the Halo universe. The sword is a Covenant weapon, presumably created by the Elites and is only used by the Elites (or the Master Chief if he manages to steal one). The blade is projected out of the hilt, which usually sits on the users waist when not in use , is usually held in one hand and when utilised allows the wielder to lunge forward and strike the enemy. The sword has shown to be very strong, even killing fully shielded Spartans or Elites and as it locks onto its target is very difficult to dodge. Along with the Shotgun, the Energy Sword is particularly effective when fighting the Flood, as dead Flood which could usually be reanimated by Infection Forms can be rendered 'unresurrectable' by slicing them into pieces with the sword. In multiplayer games, if the wielder of the weapon jumps and then attempts to lunge they execute an attack that instantly kills any normally shielded opponent and is impossible to dodge, however it is possible for two Energy Sword wielders to strike at the same time, resulting in a parry.
In Halo: Combat Evolved the sword took a blue-ethereal appearance and was wieldable only by high-ranking Elites (unless a mod was used). The Elites that wielded the sword usually used active camouflage to keep themselves hidden and kill the Chief stealthily but in terms of gameplay the glowing sword acted as a method of spotting the camouflaged enemies. In Halo 2 the sword took on a more solid appearance, blue and white in colour with tinges of purple and electricity crackling around the blade. In Halo 2 the sword was wieldable by Master Chief as well as high ranking Elites and in multiplayer had infinite energy (ammunition). In Halo 3 the sword had a lighter colour, a greater glow and had a more streamlined shape. The conditions under which the sword could be wielded were the same as in Halo 2, but the sword now had a maximum of 100 energy (ammunition) in multiplayer and took longer to draw, stopping wielders of the weapon from becoming overpowered. In Halo Wars Elites have been shown carrying Energy Swords and a trailer and concept art have even shown Elites with the capability to dual-wield energy swords, something that has not been seen in any other Halo game. The energy sword has most recently been featured in Halo: Reach in a very similar incarnation to the Halo 3 model with 100 ammo and a transparent blue color scheme. The energy sword is the only wield able weapon to have a specialty assassination.