Seven visions spamming build
Duskbringer - Lv.120
The variant you're seeing here is a cheap one. Basically you get as much as cd reduction and then keep pressing R until the creeps are all dead. Since you're in R state most of the time, you're immune to all type of damage and harm.
If you managed to get 2 gem 5 on Iron Treads and Spellfire Gloves, you can use water deity crown and stack q2 instand of r2 to deal heavy pure damage hits, making it very easy to do challenge.