Shadowflame

What is Shadowflame? 🔥

Shadowflame is a legendary Mage item in League of Legends, classified under the Mage category with keywords covering Ability Power and Magic Penetration. It fills a specific and focused niche: converting AP burst into guaranteed executes on low-HP targets through its CINDERBLOOM passive.

Where most AP items provide raw stats or on-hit effects, Shadowflame introduces a conditional critical strike mechanic for ability damage — a category previously exclusive to attack-based champions. The 40% health threshold means it activates precisely when burst mages need it most: the last 40% of a target’s HP is where fights are won and lost, and CINDERBLOOM ensures that every ability hit in that window deals amplified damage.

It is limited to 1 Shadowflame per champion and is available in SR 5v5, ARAM, Nexus Blitz, and Arena.

📊 Base Statistics & Cost

🔨 Recipe & Components

Shadowflame builds from two components that both contribute pure AP — making it one of the most straightforward AP item build paths in the game:

🔥 Passive Mechanic: CINDERBLOOM

CINDERBLOOM is a passive that triggers a conditional critical strike: your magic and true damage critically strikes for 120% damage against enemies who are below 40% of their maximum health. This is not a chance-based proc — it is a guaranteed critical strike on every damage instance when the target is below the health threshold.

What this means in practice: every ability hit you land against a target below 40% HP deals 20% bonus damage. For a 600-damage ability, that’s 120 extra damage per hit. For a multi-hit or multi-ability combo, the damage amplification compounds across every individual instance.

The CINDERBLOOM Formula

CINDERBLOOM uses a specific formula rather than a flat percentage. Understanding the math is essential for evaluating interactions with other critical damage modifiers:

Critical Damage Modifier Interactions — The Full Math

CINDERBLOOM multiplies the 20% amplifier by the product of all critical damage modifiers active. This creates specific outcomes depending on what the attacker and target have equipped:

What CINDERBLOOM Affects — And What It Doesn’t

🏟️ Arena Mode — Map-Specific Differences

Arena reduces the raw stats but adds a significant new effect. The base AP drops to 90 and magic pen to 10, and the CINDERBLOOM threshold damage is slightly reduced to 115%. However, Arena introduces a new passive layer: damage instances that already critically strike are increased by an additional 20%. This means Arena Shadowflame functions as both a low-HP execute amplifier AND a general critical-strike damage booster for champions with crit-scaling abilities.

Strategic implication: In Arena, Shadowflame is more broadly valuable — it’s no longer purely reactive to the below-40% threshold. Any champion with ability-based critical strikes benefits from the 20% amplification on those crits even against full-HP targets, making it a stronger buy across all stages of a round.

🎯 Best Champions for Shadowflame

Shadowflame is strongest on burst mages whose damage model involves multiple ability hits against targets they’re already chunking down. The 40% health threshold activates late in a combo — which means champions with front-loaded single-hit burst get less value than champions whose combo involves hits at multiple points throughout the target’s HP loss.

✅ Ideal Picks

• Syndra — Her Dark Sphere (Q) balls can be thrown at any time, and Force of Will (W) + Unleashed Power (R) deliver multiple ability hits. With targets frequently in the 40% HP range during her combo window, CINDERBLOOM activates across several of the spheres during her burst.
• Orianna — Her sustained ability presence through Command: Attack (Q) and Command: Dissonance (W) means she regularly lands damage on targets who are already below 40% HP from earlier hits. The AP and magic pen both scale her shield and damage values.
• Viktor — Power Transfer (Q), Gravity Field (W), and Laser (E) chain together with multiple hit opportunities. Death Ray in particular can hit multiple times in a single cast through augmented forms, each instance CINDERBLOOM-amplified below threshold.
• Lux — Final Spark (R) is a wide damage beam that hits everyone in its path. Against grouped enemies at low HP (after a burst phase from your team), CINDERBLOOM turns her ult into a guaranteed AoE execute amplifier across all targets below 40%.
• Veigar — His Primordial Burst (R) already executes at low HP — CINDERBLOOM stacks multiplicatively with that execute mechanic, amplifying the damage further against targets in the execution threshold. His stacking AP also means Shadowflame’s 110 AP sits on top of a naturally high AP total.
• Zoe — Paddle Star (Q) into Sleepy Trouble Bubble (E) followed by another Q deals damage across a tight window. Targets below 40% HP when the second Q hits receive CINDERBLOOM amplification on top of the already-high hit value.
• Cassiopeia — Twin Fang (E) spam against poisoned targets deals repeated hits. With a target below 40% HP during Cassiopeia’s sustained poison chain, every Twin Fang hit is CINDERBLOOM-amplified — the DPS accumulation can become extreme.
• Ahri — Orb of Deception (Q) passes through targets twice. Spirit Rush (R) delivers three charges of Essence Theft (E). Multiple ability hits in quick succession mean CINDERBLOOM activates across several instances once the target is below threshold.

❌ Suboptimal Picks

• Single-ability burst mages (e.g. Zed with AP — not applicable, Vex with one large hit): Champions whose entire burst is front-loaded into one high-damage hit rarely get to the below-40% phase before the target is already dead. CINDERBLOOM activates late in the combo — if the combo is one hit, there’s nothing left to benefit from the passive.
• AD assassins / physical damage dealers: Shadowflame provides AP and magic penetration. Physical damage champions gain nothing from either stat. The passive also specifically applies to magic and true damage — regular physical auto-attacks are explicitly excluded.
• AP tanks and utility supports: Champions who build AP for utility (Lulu, Janna, Nami) don’t deal enough raw ability damage to warrant a 3,200 gold damage item. Support AP items with utility passives deliver more value per gold on those kits.

⚙️ Recommended Build Paths

Burst Mage Execute Build (Core)

1. Luden’s Tempest — First item — poke AP and magic pen for early lane dominance before Shadowflame is complete
2. Shadowflame — Second item — CINDERBLOOM online for mid-game teamfight burst windows
3. Rabadon’s Deathcap — Third item — AP multiplier that amplifies both Shadowflame’s base AP and total AP simultaneously
4. Void Staff — Fourth item — percentage magic penetration for targets building magic resistance
5. Zhonya’s Hourglass / Banshee’s Veil — Fifth item — situational survivability based on threat type (AD vs AP)

Veigar / Syndra Stacking Build

6. Shadowflame — First item — early CINDERBLOOM threshold alignment with Veigar’s stacking AP amplifies the passive value
7. Horizon Focus — Second item — amplifies damage against immobilized or distant targets, pairs with CINDERBLOOM for double conditional amplification
8. Rabadon’s Deathcap — Third item — Veigar’s stacking AP benefits most from Rabadon’s multiplier at higher AP totals
9. Mejai’s Soulstealer — Situational — snowball stacks compound with CINDERBLOOM against low-HP targets
10. Void Staff — Fifth item — necessary against any MR-stacking response to high AP totals

🔄 Similar Items & Alternatives

Shadowflame competes in the high-AP second or third item slot against other mage legendaries. The choice depends on whether the 40% threshold conditional damage outperforms alternative forms of AP amplification for the specific champion:

❌ Common Mistakes & How to Avoid Them

• Expecting CINDERBLOOM to trigger above 40% HP: The passive ONLY activates against targets below 40% maximum health. Against full-HP or even 50% HP targets, Shadowflame is purely a stat item. Players who expect the execute passive to accelerate fights from the start are misunderstanding the threshold design.
• Front-loading the highest-damage ability before the threshold: If the biggest hit in your combo fires when the target is at 60% HP, it lands with no CINDERBLOOM amplification. The correct rotation saves higher-damage abilities for after the target has been chipped below 40% through poke or the opening of the combo.
• Ignoring the multiplicative interaction with Infinity Edge: On AP champions who also build Infinity Edge (extremely niche, but theoretically possible), the CINDERBLOOM formula compounds with the IE damage modifier. In practice, most AP mages don’t build IE — but for hybrid ability-crit builds (e.g. Corki, Ezreal), this interaction matters and delivers 126% instead of 120%.
• Building it against MR-stacking enemies without Void Staff: Shadowflame’s 15 flat magic penetration is strongest in the early-to-mid game against champions with no MR items. Once enemies stack Banshee’s Veil, Force of Nature, or Spirit Visage, the flat pen becomes less effective than percentage penetration. Always pair Shadowflame with Void Staff against MR-heavy compositions.
• Forgetting that Ignite (summoner spell) does not trigger CINDERBLOOM: Ignite deals true damage but is explicitly excluded from CINDERBLOOM’s amplification. Don’t count on Ignite + Shadowflame as a combo finisher — the Ignite ticks after the 40% threshold won’t benefit from the passive.
• Undervaluing Arena’s new 20% crit amplification effect: In Arena, CINDERBLOOM gains an additional layer that boosts already-crit damage instances by 20%. Players who treat the Arena item identically to the SR version miss this extra interaction — especially relevant for champions with ability-based crit scaling (Zoe, Corki).

✅ Best Practices

• Poke targets to 45-50% HP before committing your burst: this ensures CINDERBLOOM is active for your highest-damage hits in the combo, rather than being offline during the opening
• Against targets below 40% HP, prioritize ability usage over waiting — every hit is CINDERBLOOM-amplified, so faster ability application means faster damage accumulation
• Pair with Rabadon’s Deathcap: the AP multiplier compounds with CINDERBLOOM’s execute amplification — higher AP means larger CINDERBLOOM bonus since the 20% applies to a bigger base damage number
• Against MR stacking: buy Void Staff as the next item after Shadowflame — flat pen (15) vs percentage pen (40%) comparison shifts heavily toward Void Staff against targets with 100+ MR
• In Arena, build Shadowflame earlier than usual — the 20% crit-amplification on existing crits makes it relevant from the first round, not just as a cleanup tool
• On Veigar and Syndra: delay activating your primary burst ult until the target is close to or below 40% HP — ensure CINDERBLOOM is active for the highest-damage instances of their ults

FAQ

Q: Does CINDERBLOOM apply to DoT (damage over time) abilities?

A: A: Yes — CINDERBLOOM applies to all ability damage including damage over time effects. Each individual tick of a DoT ability that hits a target below 40% maximum HP is CINDERBLOOM-amplified. This makes DoT-heavy mages like Cassiopeia and Brand particularly strong with Shadowflame — sustained damage chains below the threshold receive amplification on every tick.

Q: Does Ignite trigger CINDERBLOOM?

A: A: No. Summoner spell damage is explicitly excluded from CINDERBLOOM’s amplification. Ignite ticks deal true damage but do not benefit from the passive even against targets below 40% HP. This is an intentional exclusion — plan your combo accordingly and don’t rely on Ignite ticks as CINDERBLOOM-amplified finishers.

Q: How does CINDERBLOOM interact with Infinity Edge?

A: A: Infinity Edge’s critical damage modifier is factored into CINDERBLOOM’s formula as a critical damage modifier. Instead of 20% bonus damage at the base (1.0 modifier), Infinity Edge increases it to 26% bonus damage (1.3 modifier). The formula is: increased damage = base + (base × 0.2) × (1 + 0.3) = 126% total damage.

Q: Does CINDERBLOOM apply when a target enters combat at below 40% HP (e.g. jungle monsters, objective buffs)?

A: A: CINDERBLOOM only activates on damage instances against targets already below 40% of their maximum health at the moment the damage is applied. If a target starts a fight below 40% (e.g. a low-HP jungle monster), yes — CINDERBLOOM applies immediately on the first hit. It does not apply to structures regardless of HP.

Q: Does CINDERBLOOM work on area-of-effect abilities against multiple low-HP targets?

A: A: Yes. Each individual target hit by an AoE ability is evaluated separately against the 40% threshold. If multiple enemies are below 40% HP when Lux R fires, CINDERBLOOM amplifies the damage against each qualifying target individually — making Shadowflame exceptionally powerful in grouped low-HP teamfight scenarios where multiple enemies are below threshold simultaneously.

Q: What’s the difference between Shadowflame and Horizon Focus for burst mages?

A: A: Shadowflame triggers on HP threshold (below 40%) and amplifies magic + true damage. Horizon Focus triggers on CC immobilization or long-range hit and amplifies all damage. They’re both conditional amplifiers but with different trigger requirements — Shadowflame is stronger in burst combos where you control when the target drops below 40%, while Horizon Focus rewards CC-lock compositions where the target is reliably immobilized.

Q: Is Shadowflame worth buying if the enemy team builds Randuin’s Omen?

A: A: Yes, though with reduced effectiveness. Randuin’s Omen’s Resilience is factored into the CINDERBLOOM formula as a negative modifier, reducing the amplification from 20% to approximately 14%. Shadowflame still contributes the 110 AP and 15 flat magic pen regardless of Randuin’s — the CINDERBLOOM passive is weaker against that specific item, but the raw stats remain unaffected.