Can you stack Contagion? | EN World Tabletop RPG News & Reviews

The general rules for spells state that spells of the same name do not have their effects combine, only the highest level effect applies. As there is nothing in the contagion spell specifying it can stack the answer would be no.

I agree. If the spell had a duration of "Instantaneous" (i.e., it provides the vector for infection but the disease itself continues without magic), it would be possible to stack multiple diseases. However, since the duration is "7 days," that means the disease remains linked to the spell, and so the spell stacking rules come into play. Specifically:

The most potent effect — such as the highest bonus — from those castings applies while their durations overlap, or the most recent effect applies if the castings are equally potent and their durations overlap.

I would rule that "most potent" refers specifically to numerical effects that can be directly compared, and does not address balance questions (e.g., Slimy Doom is more powerful than the other diseases, but not in a way that can be directly compared). Thus, the most recent effect applies.

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