Luna + Primal Beast

Why this works

Combining ultimates can be awkward for this pair. Primal Beast excels at using Pulverize to hold a single enemy in place, but Luna's Eclipse hits random targets in an area around her. She can't guarantee her ultimate will focus the hero Primal Beast has locked down. While Luna's Lunar Blessing does provide a damage bonus to allies, Primal Beast relies more on his spell damage from Trample and his ultimate than he does on his right-clicks. The extra vision from the aura at night is helpful for his ganks, but their core abilities don't directly enhance each other.

This often leads to disjointed teamfights. Primal Beast will charge in to initiate, looking for a pickoff on a key hero. Luna, however, needs to stay at a safe distance to deal damage with Moon Glaives and find a moment to use her own ultimate without getting caught. If she follows him too closely, she becomes an easy target. If she stays too far back, she can't contribute to the kill Primal Beast is trying to secure. Both heroes end up having to play their own game rather than working together as a cohesive unit.