Because You Want to Thrust Your Dagon At The Enemy

Will you update for 7.00? the Shrapnel damage buff and cooldown reduction on his talent trees are insane.

25% cooldown reduction, 25% DPS increase on shrapnel, +4 Shrapnel charge, and +4 Mana Regen.

With Octarine Core, his Shrapnel is guaranteed online in every fight and Assassinate is only 6 second cooldown. Basically you can almost always assassinate two people in one fight. The mana regen is VERY nice with his mana problem in this build. Along with Shrines, he basically cast assassinate like throwing candies. btw, love your guide, +1 from me.

Don't buy Aghanim's Scepter on him though, the damage turned into physical and lost synergy with Ethereal Blade. (Learnt this the hard way)