Do not read this unless you don’t care about minor spoilers:
[details=Open Me]Thanks to Reddit user DRayX17, with access to the strategy guide, we have some insight into how The Sword of Crota will be used. This mission will be first available early on, around level 7, but will also be playable later on higher difficulties.
You can in fact use a sword, but only for a portion of one story mission – The Sword of Crota. Near the end, you pick up said Sword of Crota, and (according to the guide) “picking up the Sword of Crota replaces your gun and super ability. It is an extremely powerful melee weapon that can tear through weaker enemies.”
The guide also mentions that “If available, use the Sword of Crota’s super attack on the boss and use the weaker Hive units to build it back up.” After the mission (the first time), you get the item Blade Shards which you can trade for an armor upgrade.
Sword controls:
Button Press Move
R1 Quick Attack
R2 Hard Attack
R1, R1 2-hit combo
R1, R1, R1 3-hit combo
R1, R2 2-hit hard combo
R1, R1, R2 3-hit hard combo
R1 (in air), R2 (in air) 2-hit air combo
R1 + R2 (with full super meter) Super (can be cancelled and linked into any combo)
Only one person in your fireteam can pick up the sword.
[b][u]SOURCE[/u][/b][/details]
Pretty sick if you ask me 
