Requirements
You must have completed In Pyre Need to gain access to the Phoenix Lair. In addition, you will need level 51 Slayer.
You will need to bring a knife, a pair of secateurs and a tinderbox in order to construct the pyre to call the phoenix to battle. You also cannot use the phoenix familiar or have a pet phoenix out while in the Phoenix Lair.
The Phoenix Lair can only be completed once per day.

Rewards
1000 Crafting
7500 Firemaking
3000 Fletching
500 Slaye