From Halopedia, the Halo wiki
The curveblade is a Sangheili melee weapon. The blade was historically used for hunting and close-quarters combat, becoming the standard in those roles long before the formation of the Covenant, though variants of the ancient design continued to be used centuries later. The curveblade's design eventually developed into the Sangheili Burnblade, which eventually developed into the Type-1 energy sword, which was created through the reverse-engineering of Forerunner technology.
The curveblade is a fairly simple weapon, consisting of a single blade and a right-angled handle. Though modern designs are made using metal, the curveblade was originally crafted from hardened resin, found in trees which lined the coastal territories of Sanghelios. The quartermoon blade was a long, curving knife that was based off of the curveblade and used by floatfighters in the Refuge.
At the hilt of several ancient ceremonial curveblades are ancient Sangheili proverbs. A few of them are down below:
List of appearances