[thejeff]

Long life (and high mr) is normal for most common SCs and thugs. That makes decay largely wasted on them.

It's largely wasted on normal troops. It doesn't kill quickly enough to win the battle and who really cares if a few more regular soldiers die afterwards. It won't usually target mages, unless they're closer or large. If they're large, they're non-human and probably long-lived.

Short lived, large important units are what it's good for. Preferably low mr. That means elephants. Hydras? Maybe some other niche units I'm not thinking of. It could be useful against some of the low end human thugs. Ulm's Black Lords maybe?

The great thing about using it on elephants is that it doesn't kill them. They just get afflictions, often limp or crippled. This slows them down so they often don't even reach your troops and do less damage when they do, but your enemy has to keep paying upkeep on them. Since they're slow it's even hard to get them up front to be killed off.