From Halopedia, the Halo wiki
The energy stave, also known as the energy pike, is a Forerunner and Covenant melee weapon, consisting of a long metal staff and a bladed tip with a series of glowing panels. Different variants of the energy stave are used for both practical and ceremonial purposes.
The ceremonial energy stave features an elaborate, forked tip with ornate panels similar in color to the armor worn by the Covenant Honor Guard. They were originally used by the Honor Guard's Sangheili personnel, including the Lights of Sanghelios. Following the Changing of the Guard use of the stave fell to their Jiralhanae successors. Following the end of the Human-Covenant War Sangheili Zealots in Jul 'Mdama's Covenant irregularly used the ceremonial stave for guarding prisoners.
The energy stave's function is largely ceremonial. The Honor Guard Sangheili mostly used Type-25 plasma rifles, Type-1 energy swords, and Type-51 carbines in combat. However, they were used by Jiralhanae to subdue any Unggoy and Kig-Yar who came too close to the High Council Chamber during one of the High Prophet of Truth's sermons regarding the discovery of Halo Installation 05's "Sacred Icon".
This version of the energy stave is more ascetic in design than the one used by the Honor Guard. Metallic gray in color, it incorporates a twin-bladed tip with blue paneling. Unlike the ceremonial staves used by the Honor Guard, these weapons can also be wielded by regular Sangheili, including Stealth Sangheili. During the Battle of the Etran Harborage, a group of Sangheili guards assigned to protect the Apex Site on the shield world were equipped with energy staves. The Honor Guardsmen escorting the Prophet of Regret's on the shield world wielded combat energy staves in addition to wearing non-ceremonial armor.
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