Predecessor Builds > Drongo > Toxic Drongo Build v1

Unlock your Boomerang ability first. Storm Breaker first because it makes killing Minions & obtaining those last hits much easier.
When you buy Imperator, you will notice that massive change in your damage output & it makes you a real hard hitter & scary threat.
Sky Splitter helps a little with sustain. Only item I would be flexible with is Ashbringer. No point having Crit chance over 100% because its wasted.
Have a play & let me know what you think. :)