Fire Forged Sheath

[otsdarva24]

One of my players has recently created a sword saint (Samurai archetype) with a focus on both fire damage and fire resistance, and one of the ways he's done this is by making a fire-forged katana, however he's a bit frustrated by the fact that he can't ignite his katana while it's in his sheath so that he can do as much damage as possible with Iaijutsu. My question is; what ideas do you all have for a katana sheath that can deal at least 10 damage to a sword in 1-2 turn(s).

[GM Rednal]

I would... probably house-rule that in as a unique item that deals damage to things placed inside it. Maybe an at-will Burning Hands at CL5, targeting only things placed inside the sheath and activated by pressing something...? With a discount on the cost given its very specific nature.