I have found this thing on Jormengand's first post
Using the custom magic item rules, we can get these brilliant items: The Staff of Instant Death This item, despite its name, is not a staff in the conventional sense, but a wondrous item bolted to the front of a quarterstaff. Each staff is keyed to a particular class or alignment, and a particular skill (such as truenamers and truespeak, or chaotic good and perform (kazoo)). When a creature that has trained in the relevant skill and is of the relevant class or alignment touches the staff, it activates, causing a whirling cone of energy in front of the wielder in a 15 foot cone. Any creature who touches the cone takes 1d4 points of damage. Half of this damage is fire damage, but the other half results directly from divine power and is not subject to fire resistance. This process is repeated until the character is dead, instantly killing any character who is not somehow immune to divine damage. Market Price: 600 gp. Prerequisites: burning hands; creator must have the Sanctum Spell feat, and either the consecrate spell or corrupt spell feat, and a feat such as arcane thesis (burning hands), easy metamagic (consecrate spell) or practical metamagic (corrupt spell). The item must be made outside the creator's sanctum. Some of the prerequisites can be ignored, but if either the sanctum prerequisite or the metamagic reducer prerequisite is ignored, the cost is 1200 GP. If both are ignored, the price is 7200 GP.
Emphasis mine. I get everything else, but what I don't understand is how the damage is repeating, so why does it repeatedly deal damage?