A build pretty much copy pasted from this youtube video: https://www.youtube.com/watch?v=3Hn3WUD_Mv8 (I did not come up with this build and take no responsibility for games thrown using this build).

This build focusses on blowing up a single hero every 4 seconds with your life break - dagon combo. When facing evasive heroes like Puck or Storm Spirit, get orchid for the silence. When they're cores pop bkb, jump on their supports (flanking helps you with this a lot). Remember that life break does magical damage, so it's increased by veil of discord, be sure to use it before you jump!

The skill build is flexible, so don't worry if you need to leave flaming spears at lvl2 while you max everything else.