Energy stave
From Halopedia, the Halo wiki
The Energy Stave is a Covenant melee weapon. It is used exclusively by the Honor Guards and Light of Sanghelios. They look like a normal, metal staff, but have a series of glowing orange panels near the top.
These weapons are long staves with a spear-like end that is similar in color to the "fins" of their wielders. Not much is known about these exotic weapons, except that they have a length of 427.5 centimeters, or 14.03 feet. They do not seem to have much of a combat purpose but more a ceremonial one, as the Honor Guard Elites will use Plasma Rifle and Energy Sword and also Covenant Carbines in real combat. However, they were used by Brutes to subdue any Grunts and Jackals that came too close to the Council Chamber during one of the High Prophet of Truth's sermons regarding the discovery of the Sacred Icon. This weapon is never used in game-play by other characters.
Appearances
Halo 2
They can be seen in the hands of the Brute Honor Guard during both the opening and closing cinematic of the Halo 2 level Gravemind, but they are simply tossed aside, as the Brutes prefer other weaponry to safeguard the Hierarchs and kill the Master Chief.
Halo 3
The Energy Stave can also be seen in Cortana occasionally.
Novels
It is also featured in the novelization Contact Harvest when the two San 'Shyuum go to the minister to recruit him as a Hierarch. It is never used against, or by, the player in gameplay.
Also, after the replacement of the Elites in the Covenant Hierarchy, the weapon's religious significance died out. During the cutscene where the brutes take power you see them fighting over the Energy Staves, meaning the Honor guards that have the pikes could have a higher value or rank than Honor Guards who don't have them at all.
Halo Wars
An early version of the weapon can be seen in a Halo Wars cinematic, it's not used in gameplay, only in cinematics. It can though been seen in combat for the first time here and there abilities finaly guaged.
In the cutscene the weapon can be seen to cut though another pike as well as peirce an Elite shields on contact and shear through their armour. The stave can also been seen used as a thrown weapon to great effect this suggests the weapon is relativly light.
This stave may have been completely remodeled into the one we see in Halo 2 and 3 as many aspects have changed so this cannot be used to assess the Halo 2 and 3 era weapon.
Gallery
An Honor Guard Elite holding an Energy Stave.
