Kaustra duration, at level 60 and 211 Dark magic skill is exactly 60 seconds. Matches well with my previous assumption, so I'm proposing a tentative duration of:

Kaustra duration (in ticks) = 1 + [(Dark Magic skill)/11]


Not exactly based in a lot of data points, but not being in the test server doesn't give me a lot of options. BTW, Up in Arms is a total joke with Embrava, Kaustra and Helices available.