Type-1 energy sword (Earth-2042)

"A noble and ancient weapon, wielded by the strongest of Sangheili, requires great skill and bravery to use, and inspires fear in those who face its elegant plasma blade."

- Supreme Commander Thel 'Vadamee

The Type-1 Energy Weapon/Sword (T-1 EW/S), commonly known as the energy sword or the plasma sword, is a traditional Sangheili close-quarters weapon. The energy sword is intended to express its owner's personal skill, clerical honor, and combat viability.

Source

 * https://www.halopedia.org/Type-1_energy_sword