User blog comment:Herzog de Puce/Baeny, the Mana Engineer/@comment-24364644-20140623134921/@comment-7709681-20140623170234

@ Blursk:

And about that passive: If you have fear because of the Q and W plus the passive, the highest amount of Mana that I was able to calculate was 4045 (Base Mana + fully stacked +  +  + fully stacked  + 300 farm + 20 kills, without masteries), and the highest amount of bonus damage it would reach with the recommended build would be   on a single strike, the first strike and having you full mana pool; that's for your information ~ bonus damage.

From the first strike and any further the damage will abruptly decrease not only due to  mana cost but the percentual cost of the abilities, comparing it with and its stable damage isn't fair; for instance, Nasus requires to kill ~117 minions (Or ~58 Neutral Monsters and Champions) to reach the aforementioned bonus damage.