From Destinypedia, the Destiny wiki
The Cleaver is a Hive melee weapon that is normally carried by Knights. Ordinary cleavers are made of bone and metal and are of little value, but special swords exist that can be wielded by Guardians under specific circumstances.
Picking up the Cleaver will change the camera perspective to third-person. Pressing the melee button will do a quick swing, which can be tapped rapidly to do a combo. Pressing the fire button will do a more powerful swing. It's possible to string together two quick swings followed by one powerful swing to get a very fast yet powerful combo. Finally, if a player's Supercharge meter is full, activating one's super will make the blade release a shockwave. Switching weapons will drop the sword, though grenades can still be used with the sword.
Sword of Crota
During the story mission The Sword of Crota, the player picks up a Cleaver that belonged to Crota, Son of Oryx. This weapon is said to consume the Light of Guardians, but does not adversely affect the player during the mission, although the Ghost states that the power it has is dark which still has it’s hazards. The player then has to use it to defeat the three Swarm Princes, after which the sword disintegrates and the mission ends.
The chosen weapon of the Blades of Crota, an elite order of Hive Knights frequently seen on Earth and the Moon during The Dark Below. Killing this knight will drop an Ascendant Sword, which functions very much like the Sword of Crota, except that it will break after about 30 seconds. Four swords also appear in the Quest Ritual of Sacrifice. In Crota's End, the Ascendant sword is dropped by Swordbearers, and is the only way to kill Gatekeepers and Crota.
The sword of Oryx, the Taken King, used exclusively by him in battle until his defeat in Regicide. Eris Morn retrieved its core to help the Guardian create Bolt-Caster, Dark-Drinker, and Raze-Lighter.
List of appearances