From Dota 2 Wiki
- Dark Seer's strength lies in his high-mana cost skills. Gets rid of his mana (ergo, he can neither use Surge to escape, nor any of his offensive skills to fight).
- makes Dark Seer not deal any damage with his skills to Ember Spirit.
- is very dangerous to Dark Seer, because even if he tries to escape with Surge he will lose all of his mana and get stunned.
- makes landing the Vacuum and Wall of Replica combo harder.
- Oracle can remove Dark Seer's Ion Shell and/or Surge by casting . This makes any gank attempt on Dark Seer in the laning phase very likely to succeed.
- prevents all magical damage that comes from Dark Seer's abilities.
- A Sniper who is somewhat competent at positioning will never be hit by any of Dark Seer's spells thanks to .
- Dark Seer relies on surge for most of his mobility, so he's not very vulnerable to slows, but much more to root effects and walls or psedo-walls such as 's or 's .
- Dark Seer's only disable is Vacuum. Though he starts off with high armor and health, he'll eventually have a hard time dealing with high mobility heroes such as or , either killing them or escaping from them.
- prevents Dark Seer from using Surge and running away.
- can deal much damage to Dark Seer if he uses his Ion Shell on a creep.
- can purge off Ion Shell and Surge.
- Ion Shell is a very powerful weapon against Broodmother's Spiderlings. It makes her laning much harder.
- Ion Shell destroys 's protection stacks in short time.
- can be destroyed fast with Ion Shell.
- Heroes that rely on illusions will suffer against Ion Shell, which kills them very quickly:
, , , .
- Heroes that rely on illusions typically spawn very strong illusions inside your Wall of Replica that you should use against them or their team.
- Melee heroes have a hard time laning against Dark Seer because of Ion Shell
Works well with...Bounty Hunter
- Ion Shell on Bounty Hunter allows Bounty Hunter to do a lot of damage while staying invisible.
- gets along with Dark Seer for the following reason - synergizes well with Vacuum and both heroes' ultis.
- Ion Shell on Riki allows him to do a lot of damage whilst staying invisible.
- Dark Seer's Ion Shell along with gives both Luna and Dark Seek big advantage to farm, while Surge gives Luna bonus movement speed to escape pursuits or to chase fleeing heroes, Vacuum is also a good setup for .
- Since 's can stun enemies in a small area, Dark Seer can use his Vacuum to pull enemies into the spot allowing to hit all enemies at the very spot.
- Sven can kill heroes that got pulled together by Vacuum very quickly due to his
- Surge is a partial solution to Sven's early game lack of mobility allowing him to close in on his targets with ease.
- provides a great setup for Dark Seer to run heroes down with Ion Shell.