How to counter Underlord

In lane

Lifestealer
• Underlord cannot trade with Lifestealer in lane at all due to Feast. • The damage reduction of Atrophy Aura does not matter because Lifestealer deals max HP damage with Feast. • Lifestealer can use Rage to make Firestorm and Pit of Malice USELESS.
Slark
• Underlord cannot trade with Slark in lane at all due to Essence Shift. • The damage reduction of Atrophy Aura does not matter because Slark steals stats with Essence Shift. • Slark can use Dark Pact to dispel Firestorm and Pit of Malice.
Juggernaut
• The damage reduction of Atrophy Aura does not matter, as Juggernaut's main damage in lane is Blade Fury. • Juggernaut can use Blade Fury to dispel Firestorm and Pit of Malice. • Underlord is a relatively slow hero that cannot escape from Blade Fury and Omnislash.

Rubick
• Firestorm and Pit of Malice are some of the best abilities to Spell Steal in the game.

Black King Bar
• Firestorm and Pit of Malice are great spells. Unfortunately they do not do anything against this item.

160 DPS in 700 Radius Around Fiend's Gate
25
+0.4s Pit of Malice Root
+10% Atrophy Aura Attack Damage Reduction/Gain
20
+0.6% Firestorm Burn Damage
-5s Firestorm Cooldown
15
Pit of Malice Slows by 20%
+15s Atrophy Aura Duration
10
+5% Invading Force Movement Bonus/Damage Reduction

At level 1, before items.

Damage

62–68