Master of Duality

• A classic critical strike build on Tristana can benefit from Master of Duality: her E scales with critical strike chance and attack damage, while the augment can quickly build ability power, letting E deal 4,000 damage.³
• A full tank Volibear build with Mystic Punch and Master of Duality can build up high ability power and attack speed.⁴
• A full tank Udyr with Protein Shake, high ability haste and Master of Duality can repeatedly cast abilities while gaining ability power and shields.⁵
• Master of Duality can work with Riven.⁶

• Master of Duality stacks gained before a round affect Megamind's level 1 shield. Upgrading Megamind to level 2 refreshes the shield after four seconds using current ability power.⁷
• With Double Tap, Jewelled Gauntlet and Ethereal Weapon, Blitzcrank's R keeps triggering after one basic attack and continues until enemies die.⁸
• Fan the Hammer with Master of Duality grants about 300 ability power per hit because the on-hit effect applies 100% of the ability power instead of 20%.⁹
• With Moonflair Spellblade, Orianna's Q, W and E can each reset her basic attack; hitting with them quickly stacks Master of Duality repeatedly.¹⁰¹¹
• Auto-casts count as ability casts for Master of Duality.¹²
• Adapt or Escapade can pair with Master of Duality, depending on which stat is needed.¹³
• High attack damage from Master of Duality can help Fiora and Decapitator deal more than 100% true damage with a single vital.¹⁴
• Mystic Punch, Reverberation and Master of Duality can pair with Transcendence.¹⁵

Master of Duality and Ethereal Weapon appeared together in repeated games.¹⁶

• With Moonflair Spellblade on Renekton, W counts as 25 ability uses and instantly stacks Master of Duality 25 times per cast.¹⁷

Earlier formats

• Since patch 14.18, Aurora's Q2 no longer triggers Master of Duality several times when cast rapidly.¹⁸ 8x2 duos
• Since patch 14.14, Big Brain's shield amount is no longer increased by Master of Duality during the preparation phase.¹⁹ 8x2 duos
• Bel'Veth's E can stack Master of Duality to full.²⁰ 8x2 duos
• Pandora's Box could turn Contract Killer into Master of Duality without changing the displayed augment; Contract Killer then stopped functioning, and the post-game screen still showed Contract Killer.²¹ 8x2 duos
• Firefox counted as an ability cast for Master of Duality.²² 8x2 duos
• Skarner's two Q casts each stacked Master of Duality.²³ 8x2 duos
• Ambessa's passive dash counted as an ability cast for Master of Duality.²⁴ 8x2 duos
• Firefox counted as both a spell cast and spell damage, triggering Master of Duality.²⁵²⁶ 8x2 duos
• Kinkou could work with Master of Duality; one or two procs were enough if stacks were built most of the time.²⁷ 8x2 duos
• Bel'Veth's E stacked Master of Duality to full; she could reach 4,000 ability power and deal a sudden 1,000–2,000 damage with W.²⁰²⁸ 8x2 duos
• An Udyr build used Master of Duality with a cooldown-reducing augment, full tank items and repeated Awaken casts to stack ability power.²⁹ 8x2 duos
• Reverb with a tanky build could stack Master of Duality until it dealt substantial damage later in the game.³⁰ 8x2 duos
• Malphite's basic attack and spell resets stacked attack damage and ability power quickly with Mystic Punch, Moonflair Spellblade and Master of Duality.³¹ 8x2 duos
• Edge of Duality with Ethereal Weapon on Katarina could sometimes grant over 1,000 ability power from one ultimate.³² 8x2 duos
• Auto-casts counted as ability casts for Master of Duality.³³ 8x2 duos
• Auto-casts did not count as spellcasts for Master of Duality.³⁴ 8x2 duos
• Master of Duality no longer triggered repeatedly for each ability use after an ability's initial missile launched and during the recast grace period.³⁵ 8x2 duos
• Shield ability power ratios no longer incorrectly included ability power gained from Master of Duality stacks during the shop phase.³⁶ 8x2 duos
• Kog'Maw reached 5,000 ability power with Master of Duality.³⁷ 8x2 duos
• Xin Zhao used Master of Duality with Tap Dancer, Symphony of War and Marksmage in a hybrid build.³⁸ 8x2 duos
• Rek'Sai used Master of Duality with a mostly tank build.³⁹ 8x2 duos

Ezreal could stack Master of Duality with Slow and Steady, Adapt and Eureka.⁴⁰ 8x2 duos

Ethereal Weapon works with Master of Duality, so each ability grants attack damage and ability power.⁴¹ 8x2 duos

Master of Duality with Escapade lets each Q increase Zeri's attack damage.⁴² 8x2 duos

Zeri's Q may need to hit a target to stack Master of Duality.⁴³ 8x2 duos

Master of Duality stacks could disappear after the champion was forced away from minion waves and could not hit champions.⁴⁴ 8x2 duos

Master of Duality could pair with Mystic Punch and Apex Inventor.⁴⁵ 8x2 duos

• Urgot's W did not gain damage from Master of Duality and Escapade, while his leg attack did.⁴⁶ 8x2 duos
• Urgot's Kinkou proc dealt 50% true damage with Escapade and Master of Duality.⁴⁷ 8x2 duos
• Master of Duality and Tap Dancer benefit from extra minions to farm stacks from, especially when those minions have extra health.⁴⁸ 8x2 duos