Can I build a deck together with friends on TCGSwap?

Yes. Every deck on TCGSwap has a Collaboration Space. You can invite up to 5 friends; they can suggest card changes, discuss ideas, and playtest proposals. You review and apply suggestions before anything changes in your deck.

How does deck collaboration work?

It works like a pull request for your deck. Collaborators open the deck editor, make their proposed changes, and submit a suggestion with a note. You get notified, open the comparison view to see exactly what they changed, and choose to apply all, cherry-pick individual cards, or decline. Nothing changes in your deck until you approve it.

Can collaborators chat and discuss the deck?

Yes. The Collaboration Space has a shared group discussion thread for the whole deck, plus a per-suggestion Q&A thread for each proposal. You can @mention teammates and link specific cards inline.

Is collaborative deck building free?

Yes, collaboration is free for all TCGSwap users during beta. You can invite up to 5 collaborators per deck.

Does TCGSwap work for MTG, Pokémon, Yu-Gi-Oh and One Piece collaboration?

Yes. The Collaboration Space supports all four games — Magic: The Gathering, Pokémon TCG, Yu-Gi-Oh and One Piece. Format validation and card prices are included for each game.

Knightmare Mermaid · Flames of Destruction Special Edition 3679218/4

Knightmare Mermaid (Flames of Destruction Special Edition 3679218/4), Rare. Market price $0.22, unchanged this week. Prices are estimates from TCGPlayer and Cardmarket, not guaranteed values.

1 "Knightmare" monster, except "Knightmare Mermaid" If this card is Link Summoned: You can discard 1 card; Special Summon 1 "Knightmare" monster from your Deck, then, if this card was co-linked when this effect was activated, you can draw 1 card. You can only use this effect of "Knightmare Mermaid" once per turn. Monsters on the field lose 1000 ATK/DEF, unless they are co-linked.

Weekly price history

Week	Market price
2026-W31	$0.24
2026-W32	$0.24
2026-W33	$0.24
2026-W34	$0.24
2026-W35	$0.24
2026-W36	$0.24
2026-W37	$0.24
2026-W38	$0.22
2026-W39	$0.22

Questions

How much is Knightmare Mermaid 3679218/4 worth?

Knightmare Mermaid from Flames of Destruction Special Edition (3679218/4) has a market estimate of $0.22, unchanged this week. Prices are estimates from TCGPlayer and Cardmarket.

Is Knightmare Mermaid 3679218/4 rare?

It is a Rare from Flames of Destruction Special Edition, a 4-card set.

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