Dawnbreaker + Lich

Why this works

A big teamfight breaks out and Dawnbreaker channels Solar Guardian on a teammate in the middle of it. The landing creates a huge stun zone, locking down several enemies at once. This gives Lich the perfect window to use Chain Frost. With the targets stuck in place, they can't spread out to dodge the bounces, and the ultimate rips through their health bars. Dawnbreaker is then free to clean up with Starbreaker on the survivors, who are often slowed and damaged enough that they can't escape.

The threat of this combination forces enemies to play apart from each other, which makes it harder for them to take objectives or focus a single target. The primary goal for Dawnbreaker and Lich is to force these clustered fights. To counter this, you need excellent vision to see the Solar Guardian coming and split up before she lands. Trying to burst the relatively fragile Lich before he can get his spells off is also critical. If he's out of the picture, Dawnbreaker's initiation loses most of its follow-up damage and becomes far less scary.