Ramping damage, lifesteal/sustain, and scaling ramp damage.
Improved attacks and sustained damage
Attacking a champion 3 times will expose them, dealing bonus damage and causing them to take more damage from all sources for 6 seconds.
Excess healing on you becomes a shield.
Takedowns on enemies grant permanent Attack Speed.
Deal 7% more damage to low health champions. Gain AD/AP after kills or assists.
Empowered abilities and resource manipulation
Hitting enemy champions with a spell grants maximum mana.
After reaching 250 mana, Manaflow Band restores 1% of your missing mana every 5 seconds.
Gain increasing amounts of AD or AP, Adaptive over the course of the game.
+9% Attack Speed
+6 AD or 10 AP
Press the Attack's exposure damage synergizes incredibly well with BotRK + Black Cleaver + [R] shredding even the tankiest champions.
Overheal is a great rune for topping off your heal to sustain chip damage from the enemy, and synergizes well with the Life Steal from BotRK and Bloodline.
More Attack Speed simply means more damage per second output, especially in elongated teamfights where you are able to get several off.
Coup De Grace is a great rune for finishing of the last bit of health on champions you have shredded with Black Cleaver and Press the Attack.
Manaflow Band allows you to constantly harass and poke in lane with your abilities while allowing you to sustain.
Gathering Storm is your late game insurance policy. Paired with Press the Attack, your late game single target dueling damage will be massive.