Is hollow knight costume profitable to sell on Amazon United States?

The niche generates $34K/yr across 20 tracked products. 0 of 8 products launched in the last 360 days are still selling. 90-day search growth is -23.2%. Flapen's verdict: Skip it (36/100).

How competitive is the hollow knight costume niche?

13 brands and 15 sellers compete. The top 5 products take 59% of clicks and top 5 brands hold 82% of demand.

What do buyers complain about in hollow knight costume?

Top complaints mined from reviews: Size-Overall, Strength, Sharpness. The return rate is 3.2%.

When does demand for hollow knight costume peak?

Demand peaks in Sep–Oct–Nov; the busiest month runs 81.9× the quietest.

What does it cost to enter the hollow knight costume niche?

Listings span $12.65–$144.49; the average listing price is $36.03 (sweet spot $15–$100). The average incumbent carries 68 reviews — the moat a new listing must climb.

Hollow Knight Costume

Skip it

Weak search conversion (0.3%) — this niche doesn't clear our bar today.

Review moat

Incredible67.75

avg incumbent reviews — the moat a new listing must climb

Avg price

Incredible$36.03

avg listing price — sweet spot $15–$100

Price range

Good$12.65–$144.49

cheapest to priciest tracked listing — scored on the share inside $15–$100

Quality gap

Good4.5★

avg incumbent rating — lower means beatable quality

Returns

Okay3.2%

return rate — above 5% kills the launch gate

Competition

Okay59%

top-5 click share — leaders hold, buyers still browse

Brand share

Okay82%

top-5 brand share — brands hold most of the demand

Growth

Bad-23.2%

90-day search growth — must beat 0% to launch

Market size

Bad$34K

$34K/yr · 318K searches

Conversion

Bad0.3%

search→purchase rate — share of searches ending in a sale

Signals Low Review Barrier

Is hollow knight costume profitable on Amazon?

According to Flapen's Amazon United States niche tracking, hollow knight costume is a $34K/yr Amazon United States market (318K searches/yr). The top 5 brands hold 82% of demand. Demand peaks in Sep–Oct–Nov. Verdict: Skip it — 36/100.

Data updated Jul 17, 2026 · scored weekly · How we score niches

hollow knight costume market size & sales

Units sold, revenue, conversion and listing quality across the tracked shelf.

Units sold / yr: 5K–6K; avg 250–500/product
Revenue / yr: $180K–$216K; units × avg price
Conversion rate: 0.3%
Avg BSR: #1,933
Page quality: 0%
Prime: 80%
Sponsored: 60%
Out of stock: 25.8%
Avg brand age: 40 months
Avg seller age: 201 days

Competition: brands, sellers & click share

The top 5 products take 59% of clicks — established leaders, but buyers still shop beyond them.

Brands

13 rising

Sellers

Top-5 brand share

82%

Top 20: 100%

Top-5 click share

59%

Top 20: 100%

Open market

14%

Lanmachoice38%
Colorful House15%
C-ZOFEK14%
NDJLNZ11%
Generic5%
UQJE4%
Open — no brand owns it (7 brands, 14%)

hollow knight costume demand & seasonality

Weekly Amazon search volume, last 90 weeks — -23.2% search growth over the last 90 days.

Peak months: Sep, Oct, Nov · busiest ÷ quietest = 81.9×

Open Trend

Top hollow knight costume search terms shoppers use

The exact queries shoppers type, with yearly volume, growth and conversion.

hollow knight costume150K/yr -23.9%0.8% conv.
hollow knight mask75K/yr -27.5%0.7% conv.
hollow knight cosplay24K/yr -14.0%0.4% conv.
hollow knight hollow knight halloween cosplay costume43K/yr -30.6%0.3% conv.
hollow knight helmet7K/yr -15.8%0.5% conv.
hollow knight costume kids11K/yr -19.3%0.0% conv.
hollow knight costumes3K/yr -2.7%0.0% conv.
hollow knight halloween costume5K/yr +27.7%0.0% conv.

All search terms

Top hollow knight costume products & what they sell for

Every tracked product — its share of the shelf, its review moat, and what it sells for.

Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.

Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

All 20 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

Lanmachoice White Knight Mask with Round Horns Cosplay Costume pvc Mask for Halloween & Game-Inspired Looks

Lanmachoice$24.324.8★230 rev

Colorful House Adult Renaissance Cloak Gothic Witch Cape with Hooded Medieval Halloween Capes(Blue 39)

Colorful House$18.024.5★195 rev

NDJLNZ Knight Mask Funny Halloween Cosplay Costume Accessories Game Party Character Mask Full Head Latex

NDJLNZ$32.144.4★46 rev

Lanmachoice 3 PCS Knight Mask with Prop Sword and Black Cloak Halloween Costume Cosplay Outfit Set for Adults Costume Accessory for Party Dress Up

Lanmachoice$26.365.0★1 rev

C-ZOFEK Adventure Game Hooded Cape Cloak Gothic Cosplay Costume (Navy Blue)

C-ZOFEK$45.664.7★13 rev

Newest

by launch date

Lanmachoice 3 PCS Knight Mask with Prop Sword and Black Cloak Halloween Costume Cosplay Outfit Set for Adults Costume Accessory for Party Dress Up

Lanmachoice$26.361 rev

3mo ago

Lanmachoice 3 PCS Knight Mask with Needle Prop Sword and Red Satin Cloak Halloween Costume Cosplay Outfit Set for Adults Costume Accessory for Party Dress Up Hornets Style

Lanmachoice$24.651 rev

3mo ago

miccostumes Womens Costume Knight Cosplay Cape with Mask (red l/xl)

miccostumes$59.701 rev

4mo ago

20.8 Knight Sword Cosplay Halloween Costume Accessory for Party Stage Performance Photo Prop Silver

Lanmachoice$12.6525 rev

6mo ago

CoserWorld Knight Sword for Halloween Cosplay Costume Accessories LARP Props Silver

CoserWorld$19.3111 rev

7mo ago

What reviews say buyers love and hate about hollow knight costume

What buyers praise and complain about, mined from review topics.

What buyers love

Quality-Overall19%

“It feels extremely well made in the details are very well done and clear”

Durability10%

“it has held up”

Size-Overall9%

“a good fit”

Advertised Vs Actual Product8%

“Better than I expected”

Weight Light6%

“Lightweight Prop Sword”

Value For Money5%

“Worth it”

Design-Overall5%

“The design looks cool enough to make the bearer feel like a real adventurer”

Color4%

“The color looks nice”

Comfort-Overall3%

“comfortable”

Thickness3%

“This sword type weapon is made of thick, sturdy plastic and is a metallic silver color”

What buyers complain about

Size-Overall15%

“Large”

Strength7%

“it can be a little flimsy”

Sharpness6%

“The tip is not sharp”

Material Quality3%

“it does look like cheap plastic”

Stitch/Finish/Polish3%

“There is an obvious seam around the edges”

Value For Money2%

“it's not that cheap”

Adhesion/Stickiness2%

“The mesh on the eye holes glue is very sparse”

Flexibility2%

“the tip is bending”

Quality-Overall2%

“It does look a bit cheap”

Thickness2%

“decently thick plastic”

Top return reasons

Size-Overall38%

Material Quality20%

Length9%

Advertised Vs Actual Product6%

Chest Fit4%

Color3%

Shape/Style3%

Defective Material/Parts3%

Shoulder Fit2%

Sleeve Fit2%

Common hollow knight costume questions

Is hollow knight costume profitable to sell on Amazon United States?: The niche generates $34K/yr across 20 tracked products. 0 of 8 products launched in the last 360 days are still selling. 90-day search growth is -23.2%. Flapen's verdict: Skip it (36/100).
How competitive is the hollow knight costume niche?: 13 brands and 15 sellers compete. The top 5 products take 59% of clicks and top 5 brands hold 82% of demand.
What do buyers complain about in hollow knight costume?: Top complaints mined from reviews: Size-Overall, Strength, Sharpness. The return rate is 3.2%.
When does demand for hollow knight costume peak?: Demand peaks in Sep–Oct–Nov; the busiest month runs 81.9× the quietest.
What does it cost to enter the hollow knight costume niche?: Listings span $12.65–$144.49; the average listing price is $36.03 (sweet spot $15–$100). The average incumbent carries 68 reviews — the moat a new listing must climb.