[Lup3rcal]

I want to build a power that causes the subject to take, say 1d burning damage whenever they take damage from a different source. Think Hex or Hunter's Mark from the 5th ed of That Other Game.

I've considered building this as an innate attack that triggers repeatedly under a specific circumstance. However, by default, an innate attack deals damage once and then is done. I've considered using Trigger Cyclic (cost halved due to repeated trigger need) to remedy this, but the attack still triggers a finite amount of times. Buying a large amount of cyclic fixes this to a point, but is quite expensive.

Alternatively, I've looked at creating some sort of disadvantage package that mirrors the effect I'm looking for, using weakness and dependency for reference, but they deal damage in a scale of minutes or slower.

How would you guys go about modeling this ability? I'm all ears.