Gem-Knight Hollowcore – #BLMM-EN022
You can send 1 “Gem-Knight” Normal Monster or 1 “Gem-Knight Fusion” from your Deck to the GY; Special Summon this card from your hand in Defense Position. When your opponent activates a card or effect, while you control a “Gem-Knight” Fusion Monster (Quick Effect): You can banish 3 “Gem-Knight” cards from your GY, including this card; negate that effect, then all “Gem-Knight” monsters you currently control gain 1000 ATK. You can only use each effect of “Gem-Knight Hollowcore” once per turn.
Date Reviewed: August 26th, 2025
Rating: 3.62
Ratings are based on a 1 to 5 scale. 1 is awful. 3 is average. 5 is excellent.
Reviews Below:
King of
Lullaby
Hello Pojo Fans,
Gem-Knight Hollowcore is a grave setup card for your Gem-Knight monsters, but is also an interaction with the opponent.
Special Summon ability helps with it being a Level 7 with only 1950ATK. Combine that Special Summon ability with the fact that it is either a Foolish Burial or Foolish Burial Goods for Gem-Knight Fusion to Special Summon this and you’re in business. Gem-Knight Fusion can cycle itself back through banishing a Gem-Knight, and putting a Normal Gem-Knight into the grave instead can set up Gem-Knight Fusion to bounce itself back or give you a target for another Gem-Knight later.
Needing a Gem-Knight Fusion on the field for Hollowcore to become a negate, as well as a 1000ATK boost for all your Gem-Knight monsters (permanent) isn’t a tough sell for this archetype’s strategy. Having to banish three Gem-Knight cards on the other hand could end up being a little tough, but with Master Diamond Dispersion being able to Special Summon three non-Rock Gem-Knight Fusions and then bring itself back when you lose one via battle, you’ll have three for the banish right there…unless the game is already over because of Dispersion.
Hollowcore is a good first turn card to get Gem-Knight Fusion or a Gem-Knight Normal Monster into your grave. It is a setup card for something better that you are going to get to now that you’ve used its effect. With Phantom Quartz able to use banished Gem-Knight monsters for a Fusion Summon at the cost of 1000LP you won’t be losing out on Hollowcore’s banish ability if you happen to use it. It feels like a just in case kind of effect, when the real highlight of this card is that first effect to Special Summon Hollowcore.
Advanced- 3/5 Art- 3.5/5
Until Next Time,
KingofLullaby
Crunch$G
Next up for every archetype seemingly getting their own take of Mathmech Circular, Gem-Knights join the club with Gem-Knight Hollowcore.
Hollowcore is a Level 7 DARK Fiend with 1950 ATK and 2450 DEF. Stats aren’t too notable besides being Evilswarm-themed, and DARK Fiend can be nice, though not much for that combo in Gem-Knights. First effect lets you send a Gem-Knight Normal Monster or a copy of Gem-Knight Fusion from the Deck to the graveyard to Special Summon this card in Defense Position. Instant access to Gem-Knight Fusion so the card can start constantly recovering itself at the cost of banishing another Gem-Knight in the graveyard. You can also send the Normals you would need to play if you wanted to properly summon Ruby, Topaz, Aquamarine, or Lady Lapis Lazuli, plus it could be a monster in the grave to use Phantom Quartz’s effect to Fusion Summon using materials in the graveyard/banishment. When your opponent activates a card or effect while you control a Gem-Knight Fusion Monster, you can Quick Effect banish 3 Gem-Knight cards from your graveyard, including this card, to negate that effect and have all Gem-Knights you control gain 1000 ATK. It might be a little costly, but it gives Gem-Knights something for a first turn play or to help secure a second turn OTK. Gem-Knights didn’t have a lot to interact with the opponent, so adding this to that pool does help slightly. HOPT on both effects as we expect. Hollowcore is good for Gem-Knights, fueling your graveyard with the Gem-Knight cards you want there as well as giving you a negate just for having any of your Gem-Knight Fusion Monsters. Play 3 and hope to see it or a searcher for it for max consistency.
Advanced Rating: 4/5
Art: 4/5 So where’s the good half of Shaddoll Zefracore?
Mighty
Vee
It’s Gem-Knight Crystal’s turn at a revival with today’s card, Gem-Knight Hollowcore, a level 7 DARK Fiend monster. Just like with Gem-Knight Nepyrim from yesterday, you can search it with Gem-Knight Dispersion, Gem-Armadillo, and Gem-Knight Phantom Quartz, in addition to Nepyrim itself this time. Its stats are inverted from Crystal’s this time around, with 1950 attack and 2450 defense. Not that it’ll be using them often…
Hollowcore has 2 hard once per turn effects, which certainly beats being a vanilla like Crystal. The first effect will let you send a Gem-Knight Normal monster or Gem-Knight Fusion from your deck to the Graveyard to Special Summon Hollowcore from your hand. The Normal monster part is a cute shout-out to Brilliant Fusion and Gem-Knight Garnet, but unfortunately we won’t be using that; instead, you really want to be sending Gem-Knight Fusion, since that’ll enable the bonus effect for Gem-Knight Dispersion. Very important, remember that! Getting a free body out of the deal is also excellent, since you can search Hollowcore with Armadillo and have 2 bodies ready to go into Phantom Quartz (hey, this sounds familiar…). Hollowcore’s other effect is a Quick Effect that can be activated in your Graveyard when your opponent activates a card or effect while you control a Gem-Knight Fusion monster, letting you banish it and 2 other Gem-Knight cards to negate that effect, then boost the attack of all of your Gem-Knight monsters by 1000. This sounds like neat disruption, and it is, but the main usage of this effect will actually be Hand Trap insulation! Your combos will generally want to get Hollowcore in the Graveyard as soon as possible while fielding a Gem-Knight Fusion, which isn’t too difficult with Dispersion and Phantom Quartz, though banishing 3 is a pretty big ask even if Phantom Quartz can recycle them later. Of course, going first it’s still solid to have as disruption, and it’ll help back up your primary wincon (which, unfortunately, is either Archnemeses Protos or Number 67: Pair-A-Dice Smasher. Aiiieee!). The attack boost sounds useless, but it’s a surprisingly helpful bonus for the going-second OTK builds, which are more popular than you would think. Hollowcore doesn’t really do anything by itself, but it’s a fantastic combo piece that reliably gets Dispersion’s deck Fusion effect online while also providing a negate in the Graveyard. Most lists seem to be running 2 copies, which checks out. It is, fortunately, not a garnet.
+Enables 1-card combos with Gem-Armadillo and allows Dispersion to Fuse using the deck
+Negate can protect your combos or provide disruption
-3 banishes is heavy and requires a Fusion on the field first
-Rather bricky on its own
Advanced: 3.75/5
Art: 4/5 Nice fire sword, Crystal!
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