Abaddon vs Shadow Fiend

How this matchup plays

Trying to burst a target with Requiem of Souls becomes a problem when Abaddon is nearby. Shadow Fiend relies on that initial fear and magic damage to secure kills, but Aphotic Shield can instantly dispel the fear from an ally and absorb a good chunk of the damage. If Shadow Fiend commits everything onto Abaddon himself, Borrowed Time makes it impossible to finish the job; all that incoming damage just heals him back up instead. This forces Shadow Fiend to play around Abaddon's defensive cooldowns, which complicates his whole ganking plan.

The result is that Shadow Fiend often has to change targets or wait for a different opportunity. While Abaddon can't stop him from flash-farming the map with Shadowraze, he can consistently deny the pickoffs that let SF snowball into the mid-game. The fight becomes about who can bait the other’s key spell first. If Shadow Fiend can get Abaddon to waste his ultimate, he has a window to act. If not, Abaddon’s presence makes it too risky for SF to go for his ideal solo kills, leading to a stalemate.