This build basically lets you have the speed and defence for ganking and tanking as well as buffing your allies at the same time. The hourglass can be used while tremors is active and can make u an effective turret tanker in pushing scenarios.

Exaust is taken so that once u taunt someone, they wont get away before your allies can finish them off and the Reverie also helps with this.

Clarity helps early game for always having the mana to powerball into taunt into defence ball as well as keeping your laning partner high on mana as well.