Devs - Damage multiplier

[Futumsh]

(whatever damage you would do without it) * (non-stacking damage multiplier) * (stacking damage multiplier)

where non-stacking damage multiplier = 1 + (highest of non-stacking %damage / 100)
and stacking damage multiplier = 1 + (sum of stacking %damage, elite damage, boss damage, etc if it applies / 100)