A Firemaking cape is a Cape of Accomplishment. It can be purchased for 99,000 coins along with the Firemaking hood from Ignatius Vulcan (who can be found south of Seers' Village) by players who have achieved skill mastery in the Firemaking skill.
A player performing the firemaking cape's emote.
Like all skill capes, the Firemaking cape gives +9 to all defensive stats, and also a +4 bonus to prayer if it is trimmed, which requires a separate skill at level 99. The cape is automatically trimmed if this condition is met.
When the Firemaking cape is equipped or in the inventory, it will act as an inextinguishable light source. Because of this feature, the High and Low Alchemy spells cannot be cast on it.
It also acts as warm clothing for Wintertodt.
As of 1 August 2019, there are 80,093 current members that have achieved level 99 in Firemaking.