Natural counters to AM are every silencer (BS, NS, Doom, drow, prophet, orchid; no blink, no escape)
armor penalting heroes/items (SF, TA, Gondar, Invoker, Venge, MoC, Cuirass; he has magic resistance, but low hp and armor)
Other damage types (OD, Silencer, Ench, Tinker, Bane, Slardar, Dazzle, Jugger, Ursa; pure or physical)
even magic resistance penalting skills are enough (Pugna, decrep nullifies his shield and makes him unable to attack)
All generalizations are false... including this one.
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