User blog comment:GreenMoriyama/Nine, the Magus of Elemancy (collab w-Lesdin)/@comment-7709681-20170913024132/@comment-7709681-20170913135321

Ok, I wrote this at 1am, so I was sort of braindead in respect to calculations, so goes for the stacking. So it should be a multiplicative stacking and the increase is to the total damage dealt for what Lesdin implies, that's a maximum of 234% total damage.

However, still stand with the statement that can deal a lot of damage for the bonuses it can grants, as it seem that repeated stacks increase the bonuses based on the number of stacks as there's no indicated limitation (which already can highly scale up), and considering the potential of dealing bonus damage, slow and boost your MS, then it on itself is still strong.

3 Red stacks deal up to  without the increase, with the increase deals. Tell me that isn't high, even if it was an ultimate; the only one I can think of is an AP  with his, but this is a basic ability with a low cooldown to stack and the Innate to consider.