Multicast makes your spells proc multiple times, so spam Fireblast for huge burst and stun.

Fireblast is a point and click stun, so use it to disable key enemies.

Bloodlust boosts attack and movement speed, so keep it on your carry.

Ignite slows and damages over time, so use it to zone and finish.

Ogre has high base stats, so trade aggressively in lane as a tanky support.

Build mana regen so you can keep spamming spells for Multicast procs.