Chaos Knight + Phantom Assassin

Why this works

Focusing down a single target is the main plan here. Chaos Knight can land his Chaos Bolt, allowing Phantom Assassin to jump in and start attacking. This can secure kills on isolated heroes, especially supports who get caught out of position. The problem is that both heroes rely almost entirely on physical damage to get the job done. This makes it straightforward for the enemy team to build defensive items like armor or Ghost Scepters, effectively countering the primary threat from both your main damage dealers at the same time.

This draft puts a lot of pressure on the early and mid-game. If Chaos Knight and Phantom Assassin can't secure kills and snowball, they end up competing for the same farm on the map. This can lead to a situation where you have two cores with half the items they need instead of one fully enabled carry. The game becomes a race to see if they can end before the enemy team's defenses come online and punish the lack of magical damage or broader teamfight control from your side.