Phoenix + Slark

Why this works

The idea of locking enemies down with Supernova for Slark to build Essence Shift stacks sounds promising, but in practice, their kits can sometimes pull them in different directions. Phoenix often wants to dive deep into the enemy team to hit as many heroes as possible, creating a big chaotic teamfight. Slark, on the other hand, excels at finding a single weak target on the edge of the fight and sticking to them. While the stun from a successful Supernova can definitely create a window for Slark to attack freely, he's often slippery enough to create his own opportunities without it.

How this plays out depends heavily on the specific fight. If the enemy team clumps up, a big egg can absolutely win the fight and let Slark clean up. Phoenix can also sustain a brawling Slark from a distance with Sun Ray. But if the enemy has good burst to kill the egg quickly or ways to kite and split up, the two heroes can feel disconnected. Phoenix might die alone after a dive, while Slark is forced to use Shadow Dance to escape rather than to press an advantage. They can function together, but one doesn't consistently set the other up for success.