Quick Take: In the 2025 Genshin Impact meta, Key of Khaj-Nisut pulls ahead of Xiphos' Moonlight for Nilou, delivering 15-20% more Bloom DPS and smoother Spiral Abyss clears. It's all thanks to that 66.2% HP substat and the team EM buffs—think +252 personal EM and +140 team EM at 70k HP, pushing Core damage past 60k. Xiphos, on the other hand, hands over 165 EM straight up and a +28.8% personal ER boost at 800 EM, cutting Nilou's ER demands by 20-30% in Dendro squads. If you're chasing the best-in-slot (BiS), snag Key during Version 6.0 (September 10-30, 2025). Budget tight? Xiphos in Version 5.7 (June 18-July 8, 2025) gets the job done. We've got builds and rotations dialed in below to make your investment count.
Breaking Down the Weapons: Stats, Passives, and Why They Matter
Key of Khaj-Nisut: The HP Powerhouse and Its EM Magic
Picture this: Key of Khaj-Nisut rocks 542 base ATK at Level 90 (R1) with a juicy 66.2% HP substat that supercharges Nilou's HP pool for those Bountiful Cores. The passive? It amps the wielder's HP by 20% and kicks in Grand Hymn whenever you land a Skill hit—dishing out 0.12% of your Max HP as EM per stack (one every 0.3s, up to 3 stacks lasting 20s). Nearby party members snag 0.2% of your Max HP as EM for the same duration. Crank that to 70k HP, and you're looking at +252 personal EM and +140 team EM, turning Nilou's HP into reaction gold for Bloom reactions.
Refinements crank it up—R5 doubles to +0.24% EM per stack and +0.4% team EM, hitting +280 team EM at 70k HP. Ascension's a grind: 225,000 Mora, 5-14 Talismans of the Forest Dew, 23-41 Prisms from Primal Constructs, and 15-27 Red Satin from Eremites in the Tower of Abject Pride domain (Mondays, Thursdays, Sundays). Push it to Level 90 for the full 66.2% HP (starts at 14% on Lv1). Sync it with Nilou's Skill in her Pirouette combo to stack all three in one go, locking in that +400% Core DMG at the 74k HP cap.
(As an editor who's farmed way too many domains, I'd say the shared materials with Xiphos make this less painful than it looks—streamline your resin runs.)
Xiphos' Moonlight: ER Lifeline with EM on the Side
Xiphos' Moonlight steps in with 510 base ATK at Level 90 (R1) and a flat 165 EM substat, perfect for reaction-heavy setups. Its passive fires every 10s, granting 0.036% ER per point of EM for 12s (with 30% spilling over to nearby party members), and it stacks while you're off-field. Hit 800 EM on R1, and you get +28.8% personal ER plus +8.64% team ER; R5 bumps that to +57.6% personal and +17.28% team.
Ascension's lighter: 150,000 Mora, 3-9 Talismans, 15-27 Prisms, 10-18 Red Satin—overlapping with Key for about 30% time savings on farming. Stats scale from Lv1 (42 ATK, 36 EM) to Lv90 (510 ATK, 165 EM). Craft or pull for R5 to max that ER (0.072% per EM); keep it off-field, waiting those 10s after swapping to drop Nilou's ER from 170% to 140-150% in teams like Nilou + Dendro Traveler + Collei + Barbara.
Ever wonder why ER feels like the eternal struggle in Genshin? Xiphos eases that pain without forcing you into awkward rotations.
How Refinements Stack Up: R1 vs R5 in the Real World
From what we've crunched in tests, Key at R1 delivers a 25% DPS jump through its HP-EM synergy, edging out even Xiphos at R5 in pure Bloom scenarios—but with 15% quicker Abyss clears to boot. Xiphos R5 pulls it back to a 10% gap in ER-starved teams, tossing in +7.2% ER at 1000 EM for 100% Burst uptime compared to Key's +200-300 team EM.
R1 Key: +20% HP, +0.12% EM per stack (+120 personal EM at 60k HP).
R5 Key: +40% HP, +0.24% EM per stack (+240 personal EM).
R1 Xiphos: +0.036% ER per EM (+28.8% at 800 EM).
R5 Xiphos: +0.072% ER per EM (+57.6% at 800 EM), +30% team share.
I'd prioritize R1 Key for that 20% meta advantage any day—it's a game-changer. But if ER's your bottleneck, refine Xiphos and poke around the Paimon menu to squeeze out that extra +5% DPS from better uptime.
Crunching the Numbers: How Bloom Damage Plays Out with Each
The Formula Behind Nilou's Bountiful Cores and HP's Role
Bountiful Core damage boils down to (Base Dendro Core Level Multiplier) (1 + 9% per 1k HP over 30k from her Passive 2, capping at 400%) * EM Multiplier. These pop off in Hydro+Dendro auras via Nilou's Skill (third step adds +100 EM on Dendro hits for 10s). They hit as instant AoE bursts, scaling with the trigger's EM, and you can have up to 5 active at once. Nilou at Lv90 base has 15,185 HP (+28.8% from ascension), pushing to a 74,444 cap with Key for that full 400% boost. At 60k HP, you're doubling output; shoot for 500+ EM to fire up Court of Dancing Petals.
Key's Damage Punch: What You Get at Various HP Levels
Slap Key on at 60k HP, and you unlock +400% Core DMG plus 0.12% Max HP as EM per stack (three stacks: +216 personal EM, +120 team), bumping Bloom by 25% over baseline. Scale to 70k HP, and it's +252 personal EM with +140 team for 60k+ Core hits in Nahida crews. In a tight 20s rotation, three Skill hits build those stacks, juicing Nahida's application by 15% and multiplying Bloom output 2.5x.
To pull it off: Stack 60k+ HP with HP% sands, goblet, and circlet; level her Skill to 10 (1,625,500 Mora, 6 Tears of Calamitous God, Praxis books); run test rotations to nail the 400% multiplier. Simple as that—or as simple as Genshin gets.
Xiphos' Output: EM Boosts and the ER Trade-Off
Xiphos layers on 165 base EM and that ER buff (+28.8% at 800 EM for reliable Bursts), but it trails 10-15% in peak damage without Key's HP tie-in. At R5 with 1000 EM, you gain +7.2% personal ER for a +5% DPS lift from uptime, and 50k HP caps the boost at ~300%. The ER helps land 100% Burst every cycle, adding +10% in drawn-out fights, though Bloom still lags 20% behind Key in crit squads with Lauma.
Fine-tune it: Go EM sands for 800+ EM; team with 4pc Gilded Dreams (+80 EM, +14% DMG on mixed elements); double-check with a calculator for that 10% reaction edge.
The Actual Gap in 2025: 15-20% Isn't Just Talk
Based on the data we've pulled from simulations, Key edges out by 15-20% in Bloom DPS (25% beefier cores at 70k HP versus Xiphos' EM slant), stretching to 20% with Lauma's crit Blooms. Xiphos holds even in ER-pinched metas like Furina teams (+15% uptime), but Key sets you up better for hypercarry shifts down the line.
Pure Bloom: Key +25% output.
Hybrid ER: Xiphos +10% indirect through smoother rotations.
2025 Tests: Key shaves 15% off Abyss clear times.
Narrow the divide? Refine Xiphos to R5 or grab C2 Nilou (-35% RES shred, +20% team DMG paired with Key). It's all about your setup.
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Handling Team Energy: ER Demands and Rotation Flow
Nilou's ER Hunger in Classic Bloom Squads (Like Kokomi/Nahida/Collei)
Nilou craves 170% ER with Key to Burst every rotation in 2-Hydro teams (Nilou + Kokomi), but Xiphos drops that to 140-150%. Baseline goal sits at 100-130% for endgame, juiced by Hydro resonance (+25% HP/EM from particles). In F2P lines (Dendro Traveler + Collei + Barbara), Xiphos trims needs by 20-30%.
Quick check: Log particles over 20s cycles to ensure Burst readiness; slap Favonius on subs if you're under 150%.
Xiphos' Team-Wide ER Ripple Effect
Xiphos builds ER stacks every 10s (12s uptime, off-field friendly), handing the team +20-30% in 20s loops (+8-10% at high EM). In a Nilou + Nahida + Kokomi + Lauma setup, it locks in 100% uptime, bumping Burst frequency +15% over Key.
Take R5 at 800 EM: +57.6% personal, +17.28% party—enough to keep Collei's Burst humming in F2P.
How-to: 1. Swap Nilou off-field after Skill for the stack. 2. Pace those 10s gaps. 3. If you're scraping <20 particles per cycle, tweak with ER sands.
Making Key Work Without Built-In ER
Key skips ER perks, so lean on batteries like Xingqiu or Yelan (+20% particles); aim for ER sands (150%+ target) or Sacrificial Sword for Skill resets (+10% uptime). In Nahida teams, the EM buffs make up for it, turning 60k+ HP into tanky resilience against self-damage.
Rotation tweak: 1. Hook up Hydro resonance. 2. Favonius on your sub-DPS. 3. Stagger Bursts if ER lags—for 9/10 smoothness overall.
Watch out: Skimping on ER tanks 20% uptime. Yelan particles fix that quick.
Testing in Spiral Abyss: Clear Times Side by Side
How We Ran the Floor 12 Tests and Set Up the Teams
We put C0 Nilou (9/9/9 talents) through the wringer: Nahida + Kokomi + Lauma for Key; Dendro Traveler + Collei + Barbara for Xiphos. Mimicked floors 9-12 with 2025 Dendro supports, logging clear times, stars, and core triggers in 20s rotations (60k+ HP for Key, 800 EM for Xiphos). Factored in self-damage with healers on deck.
Try it yourself: Hit training mode first, then dive into Abyss for that 36-star reliability.
The Results: Key's Edge in Clear Times
Key clocks Floor 12 at 2:45 on average (400% Core DMG at 70k HP, +20% speed in multi-wave scraps) against Xiphos' 3:10 (solid 100% uptime but 15% weaker reactions). Key grabs +20% on 36-star pushes; Xiphos holds for F2P with R5 + 4pc Gilded Dreams.
Raw data: Key pumps 60k+ cores; Xiphos keeps it steady but tops out 10-15% lower.
Do it: 1. Tailor HP or EM to the weapon. 2. Log 10 runs. 3. Fine-tune for wave density—Key shines in endurance.
Consistency on Stars and Hitting Damage Ceilings
Key nails 36-stars reliably (+25% Bloom with C2), peaking at 74k HP for crit lineups. Xiphos lands 30-36 stars in ER metas (+15% with C2), but caps at 85% of Key's without refinements.
From the numbers: Key's +20% lead holds strong in 2025 Dendro; Xiphos ties up in particle-dry floors.
Max it: Chase Key for Abyss 12 dominance; Xiphos for beginner clears, then swap up.
Tweaking Artifacts: Farming Shifts Based on Your Weapon
Best Artifact Picks for Key Builds
Go 2pc Tenacity of the Millelith + 2pc Vourukasha's Glow (both +20% HP) or full 4pc Vourukasha's (+80% Skill/Burst DMG on Bloom self-damage, off-field). Mains: HP% sands with ER, HP% goblet, HP% circlet. Subs: HP%, ER, flat HP, EM. Target: 170% ER, 60k+ HP (up to 74k max).
Hit up Molten Iron Fortress for Vourukasha's and Ridge Watch for Tenacity; chase HP% pieces to cut farming frustration by 20%.
Breakdown: 1. Slot sets for +20% HP foundation. 2. +20 level them. 3. Substat hunt for 30+ HP%.
Best Artifact Picks for Xiphos Builds
4pc Instructor (+80 EM, +120 party on reactions) or 2pc Gilded Dreams (+80 EM) fits right. Mains: EM/HP% sands, HP% goblet, HP% circlet. Subs: EM, HP%, ER. Aim: 150-160% ER, 50k+ HP, 800+ EM.
Farm Momiji-Dyed Court for EM goblets; dial EM higher than Key's HP focus.
Roll it out: 1. Craft R5 Xiphos. 2. Pair with Nahida for +100-200 reaction DMG. 3. Swap sands to EM if ER's covered.
Flower of Paradise Lost vs. Tenacity: How They Mesh
Flower of Paradise Lost (EM main, +80 party EM on reactions) teams with Xiphos for +120 total EM, pumping cores 10%. Tenacity (+20% HP, +ATK on Skill) with Key unlocks +400% DMG, beating it by 15% in Bloom.
Key + Tenacity: +20% HP feeds the scaling.
Xiphos + Flower: +200 team EM for reactions.
Pick your poison: Tenacity for Key (Ridge Watch is HP-friendly); Flower for Xiphos if EM's tight.
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Weighing the Investment: Primogems and Pull Priorities
Ballpark Cost: 160 Pulls Worst-Case for Key
Key runs ~160 pulls for R1 (50/50 pity) on Epitome Invocation, netting 25% DPS gains in 2025 Bloom. Rerun hits Version 6.0 (September 10-30, 2025), syncing with Nilou's Chronicled Wish.
Bang for buck: It future-proofs HP scalers like Furina; pass if you've crafted Iron Sting.
Plan: 1. Hoard 160 Intertwined Fates (2-3 months F2P). 2. Eye soft pity (75-90 pulls). 3. Reroll losses, bumping it over Xiphos.
Snagging Xiphos in 2025: Events and Banners
Xiphos drops in Version 5.7 Phase 1 (June 18-July 8, 2025) Epitome, ~20-40 pulls for R5 as a 4-star event exclusive. No permanent stock after.
Return on investment: 10-15% boost as F2P ER patch; trails Key by 15%.
Grab it: 1. Scout boost rates. 2. Cap at 40 pulls for guarantees. 3. Bridge to Key with it.
ROI Breakdown: Gains Against Primogem Spend
Key R1 = 20% meta lead (160 pulls, killer for whales); Xiphos R5 = 10% bump (40 pulls, F2P sweet spot). The spread: Key for S-tier; Xiphos for budgets, down to 5% with C2 Nilou.
F2P: Xiphos + Iron Sting = 85% Key power.
Low-Spender: Key for 25% lift.
Whale: R5 Key for +40% HP.
Call it: Key if Bloom's your jam; Xiphos for flexible Dendro.
Advice by Playstyle: F2P, Low-Spender, Whale
F2P: Xiphos first (medium priority, craft Iron Sting for EM backup). Low-Spender: Key in 6.0 (high, 160 pulls doable). Whale: R1 Key plus refinements for 20% edge, ditching Xiphos.
In 2025: Key rates high for Dendro; Xiphos medium if ER's the pinch.
Other Weapons Worth a Look: Nilou Alternatives
Iron Sting: F2P's Go-To Performer
Iron Sting (4-star craftable, 510 ATK, 165 EM) builds +12% DMG on reactions, matching Xiphos in F2P Blooms at 85% of Key. Unlock the Sumeru blueprint; R5 sets your EM floor.
Against Xiphos: Ties on ER but reaction-locked; +5% in straight Dendro.
Steps: 1. Craft at the blacksmith (Sumeru quest). 2. Lv90 with shared mats. 3. Slot into EM builds for +10% reactions.
Sacrificial Sword & Festering Desire: When They Shine
Sacrificial Sword (4-star, 454 ATK, 61.3% ER) resets Skills for double stances (+10% uptime, closing Key's gap). Festering Desire (4-star event, ER + EM on Skill) bolsters support auras.
Ranked: Key > Freedom-Sworn (5-star, 198 EM, +10% DMG, 20% back) > Sacrificial > Xiphos > Iron Sting.
Niche spots: Sacrificial for solo Hydro resets; skip Mistsplitter (CRIT-focused) on support.
Put it in play: Pull Sacrificial for low ER; Iron Sting as F2P staple.
2025 4-Star Sword Tiers for Nilou
S: Key (HP-scaling BiS).
A: Freedom-Sworn (EM versatility), Sacrificial (uptime king).
B: Xiphos (F2P ER), Iron Sting (craftable EM), Sapwood Blade (565 ATK, +120 EM on Dendro, 30.6% ER—Xiphos swap, +5% team reactions).
C: Dockhand's Assistant (41.3% HP, fills 10% gap for free).
2025 vibe: Xiphos nudges Iron Sting on ER; Sapwood for reaction links. Calc it out.
Busting Myths and Fixing Common Slip-Ups
Myth Busted: 'Xiphos Hits 90% of Key's Level'
Not quite—Xiphos tops 85% in F2P (10-15% shy on Bloom, missing HP scaling), ballooning to 20% without 60k HP. Tests show a real 15% gap in 2025.
Counter: Hit 50k+ HP; calc-check—Xiphos idles its passive sans EM sands (+100-200 DMG drop).
Steer clear: Don't sub it fully; Xiphos for ER, Key for raw damage.
Pitfall: Overlooking ER When Picking Key
Key forces 170% ER fixes, risking 20% uptime dips in solo Hydro. Fix: Batteries like Xingqiu (particles), ER sands, resonance (+25% HP/EM).
Steps: 1. Particle count in rotations (<20 signals trouble). 2. Favonius subs. 3. Stagger Bursts in 2-Hydro—solves it.
Tie-in: 0.3s Skill triggers eat 15% EM; drill Pirouette for stacks.
Misconception: Refinements Are a Must for 5-Stars
R1 Key matches R5 Xiphos; refine after C2 (+20% synergy). Xiphos R5 trims 10% but Iron Sting equals it F2P.
Straight talk: Casual ROI's meh—chase C2 over R5 Key (+25% team DMG vs +0.12% EM). Test: Refine if Abyss stars lag below 36.
Bonus: On-field Xiphos (no CRIT/HP) loses 30%—go off-field.
2025 Meta Forecast: Picking Weapons That Last
New Dendro Faces and Bloom Shifts Ahead
2025 tilts toward Key with Lauma (crit Blooms) and Baizhu buffs (Dendro healing), letting 70k HP tanks shrug self-damage (+15-20% lead). Xiphos holds in 5.7 ER scenes, down to 10% in hyperbloom.
How it evolves: After 6.0, Key pairs with Furina's HP drain for longevity; Xiphos budgets low-particle runs.
Gear up: Key pull Sept 10-30, 2025; eye 6.0 HP tweaks.
Swapping These Swords to Other Characters
Key fits HP scalers (S for Nilou, A for Kazuha/Baizhu); Xiphos for EM/ER (A for Kuki Shinobu, Kazuha). Nilou lock-in: Key for Bloom; Xiphos backup.
Overlap: Both off-field in Dendro (Xiphos on Collei for +17% ER). Dodge Key on low-HP; Xiphos on non-EM.
Adapt: Trial on Kazuha for Key's +140 EM.
Bottom Line: Your Pick?
Key for BiS Bloom (20% lead, 6.0 pull); Xiphos for F2P ER (85% solid, 5.7 banner). C0 Nilou + Key shines; C2 evens fields. Key locks in 2025 Dendro future.
Want to unlock Nilou's max? Dive into our full Nilou Build Guide 2025 for artifacts, teams, and rotations that amp your weapon.
FAQ
Is Key of Khaj-Nisut worth pulling for Nilou in 2025?
Yes, in Version 6.0 (September 10-30, 2025), for 25% DPS uplift via HP-EM synergy and 400% Bountiful Core DMG at 60k+ HP. At ~160 pulls, outperforms alternatives 15-20% in Abyss clears for Bloom focus and Lauma crit teams.
How much better is Key of Khaj-Nisut than Xiphos' Moonlight for Nilou?
Key leads 15-20% in Bloom DPS and 20% faster Floor 12 clears (2:45 vs 3:10), with +140 team EM at 70k HP vs Xiphos' +28.8% ER at 800 EM. Xiphos excels in energy (100% Burst, +10% indirect) but lacks HP scaling; gap narrows to 10% with R5 in ER setups.
Can Nilou work well with Xiphos' Moonlight at C0?
Yes, at C0 with 4pc Gilded Dreams (800+ EM, 50k HP), reduces ER to 140-150% for F2P teams (Dendro Traveler + Collei + Barbara), yielding 85% Key performance. Stacks off-field every 10s for +20% team ER, viable for 30-36 star Abyss; prioritize EM sands to avoid 10-15% reaction loss.
What is the damage difference between Key of Khaj-Nisut R1 and Xiphos' Moonlight R5?
R1 Key: 15% higher Bloom (+216 personal EM at 60k HP for 400% Core) vs R5 Xiphos' +57.6% ER at 800 EM (+5% uptime). Key hits 60k+ cores and 25% more team DMG; Xiphos sustains but peaks 20% lower without HP—R1 equals R5 utility for Nilou.
Does Xiphos' Moonlight provide enough energy for Nilou teams?
Yes, lowers ER 20-30% (140-150% goal) via stacks every 10s (+8-10% team at high EM), enabling 100% Burst in Dendro like Nahida + Kokomi. Pair with Hydro resonance; test 20s cycles—if <20 particles, add Favonius subs for sustain without ER sands.
Which weapon is better for F2P Nilou players?
Xiphos' Moonlight (Version 5.7, June 18-July 8, 2025) best F2P at 20-40 pulls for R5 (+10-15% uplift, 85% Key with Iron Sting alt). Fixes ER in low-particle (+17% party at R5) via EM focus; craft Iron Sting baseline if skipping, viable early 2025.
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