Deadlock: Countering every hero

Steam Community guide by Poketape.

Introductory Disclaimer

You only have so many item slots and souls to spend, so just because you're laning against a certain opponent does not mean you need to buy items to counter them. Consider how well you're doing in-lane, as well as how other opponents are performing to see which opponents, if any, you need to obtain items to counter.
The entire enemy team composition matters as well, as many items counter multiple heroes, so consider that in your purchasing decision. Sometimes you may need to counter multiple heroes, sometimes one opponent is carrying the team, etc.
The below guide separates items by phase, but every play-through is different so don't feel like you need to strictly hold to the phase guidelines.

Abrams

Early Game

• Decay/Healbane - used for anti-heal
• Reactive barrier - counters his stuns
• Slowing bullets - slows him down; builds into silencerMid/Late Game
• Toxic bullets - used for anti-heal
• Ethereal Shift - in case you get caught in his ult

Bebop

Early Game

• Reactive barrier - counters his hook/uppercutMid/Late Game
• Debuff remover - removes his bombs
• Rescue beam - saves allies from hook
• Ethereal shift - helps with survival if hooked or if bombs are applied

Dynamo

Early Game

• Reactive barrier - counters his first ability and ultMid Game
• Knockdown - apply it pre-ult and it will prematurely end it
• Rescue beam - saves allies from his first ability and ultLate Game
• Unstoppable - counters first ability and ult
• Curse - apply it pre-ult (replaces Knockdown)

Grey Talon

Early game

• Debuff reducer - counters trapsMid game
• Debuff remover - counters traps
• Knockdown - gets him out of the airLate game
• Ethereal shift - dodge his ult

Haze

Early game

• Return fire - counters her primary fire and ultMid game
• Knockdown - prematurely ends her ult
• Warp stone - escapes her ultLate game
• Curse - replaces Knockdown and prevents ult
• Metal skin - counters her primary fire and ult

Infernus

Mid game

• Debuff reducer/Debuff remover - counter passive
• Healbane/Decay/Toxic bullets - antihealLate game
• Curse - use it to slow him down if he's charging with his ult

Ivy

Early game

• Extra stamina/Warp stone - to escape her abilities
• Healbane/Decay/Toxic bullets - antihealMid/late game
• Knockdown/Silence Glyph - knocks her out of the air and pauses her from using stone form

Kelvin

Early game

• Extra stamina - counters his slowing
• Healbane/Decay/Toxic bullets - antiheal
• Silence glyph - prevents ultMid/late game
• Ethereal shift - uses up time within his ult

Lady Geist

Early game

• Bullet/Spirit Armor
• Healbane/Decay/Toxic bullets - antihealMid game
• Silence glyph - prevents ultLate game
• Curse - prevents ult

Lash

Early game

• Silence glyph/Slowing hex - shuts down his movement abilitiesMid game
• Knockdown - stops his movement, especially useful against his ult
• Warp stone - quickly escape himLate game
• Ethereal shift - helps you wait him out if he gets you
• Curse - replaces Knockdown

McGinnis

Early game

• Monster rounds - counters turrets
• Extra stamina - counters her slowness
• Reactive barrier - if you're getting hit by her wall a lotMid/late game
• Healbane/Decay/Toxic bullets - antiheal
• Withering whip/Suppressor - reduces her damage output

Mirage

Early game

• Reactive barrier - counters his tornadoMid/late game
• Debuff reducer/remover - reduces/removes his bullet stacks as well as his scarabs' health-steal

Mo and Krill

Early game

• Reactive barrier - counters knock-up and ultimate
• Healbane/Decay/Toxic bullets - antihealMid/late game
• Slowing Hex/Silence Glyph - prevents their escape using burrow

Paradox

Early game

• Reactive barrier - counters knock-up and ultimate
• Extra staminaMid/late game
• Ethereal shift - waits out her ult
• Rescue beam - saves allies from her ult

Pocket

Early game

• Spirit armor
• Silence Glyph - he's very ability-reliant; prevents his escapeMid game
• Debuff reducer/remover - counters his ultLate game
• Curse - replaces Silence Glyph

Seven

Early game

• Knockdown - counters his ultimateMid/late game
• Curse - replaces Knockdown
• Improved spirit armor - survive his ult
• Superior stamina - run away from his ult
• Healbane/Decay/Toxic bullets - antiheal

Shiv

Early game

• Debuff reducer/removerMid game
• Knockdown - punish if he jumps in
• Healbane/Decay/Toxic bullets - antihealLate game
• Curse - punish if he jumps in; replaces Knockdown

Vindicta

Early game

• Extra stamina - escape her or close the gap
• Spirit armor - for her crow/ult
• Divine barrier - if she's trying to snipe youMid game
• Knockdown - knocks her out of the airLate game
• Curse - knocks her out of the air; replaces Knockdown

Viscous

Early game

• Extra stamina - dodge his abilities
• Silence Glyph - prevent him from using his abilitiesMid game
• Knockdown - slow him down, but not great
• Bullet resist shredder/Magic vulnerability/Escalating exposure - for when he rolls aroundLate game
• Curse - slow him down, but not great; replaces Knockdown

Warden

Early game

• Extra stamina - counters his flask and escapes his stunMid game
• Debuff reducer/remover - counters his flask and escapes his stun
• Slowing hex - prevents him from running away
• Rescue beam - save allies stunned by himLate game
• Unstoppable - if he jumps in on you

Wraith

Early game

• Reactive barrier - counters her ultMid/late game
• Ethereal shift - counter right before her ult hits
• Silence Glyph - prevents abilities as she relies a lot on cards for damage

Yamato

Early game

• Extra Health - stack up health items to counter her attacksMid game
• Slowing Hex - slows down her flying strike
• Knockdown - if she pops her ult, it will waste her ult up-time
• Silence Glyph - time right before she pops her ultLate game
• Soul rebirth