Dark Seer vs Necrophos

How this matchup plays

Clustering heroes together is Dark Seer's entire plan, using Vacuum to set up his team's damage. This plays directly into what Necrophos wants to do. The sustained area damage from Heartstopper Aura and the constant healing from Death Pulse turn those chaotic clumps into a massive advantage for Necrophos and his allies. The longer the fight goes, the more value he gets. On the other hand, Dark Seer has one of the best tools for saving an ally from Reaper's Scythe. A quick Surge allows a low-health hero to sprint out of danger, denying Necrophos a crucial kill and reset.

The result is that teamfights are often decided by a single spell. If Necrophos gets caught by a good Vacuum and his team can't support him, he falls over. If Dark Seer fails to save a key ally from the Scythe, the fight is likely lost. Both heroes create conditions that the other can exploit. Victory usually goes to the team that better executes their follow-up after the initial spells are cast, or to the side that is already further ahead when the fight begins.