Predecessor Builds > GRIM.exe > Grow Grim

If you can level all your gear you come up to 650 magic damage, 190 physical, attack speed going from 150 to 280% thanks to typhoon, 3k mana, a shield on 40% life of 750hp. Buff damage on long range ability.
It's a build focus on ability damage, the blast and ulti do a lot of damage (at max like 600 for blast and 1k for ulti), but since you have an "ADC" and a lot of mana you can spam assault mode giving you good damage with basic.