Someone with better skills in infinite series can figure this out, but here’s the series:
p = Spell effect on my Onatal (25%, 50%, 75%, 100%)
q = Spell effect on foe’s Onatel
then the mana my Onatel gains per tile (expressed in tiles) is:
p - pq + (p^2q - p^2q^2) + (p^3q^2 - p^3q^3) + …
So this:
