Link Monster

A Link Monster (Japanese: リンクモンスター Rinku Monsutā) is a type of Monster Card. The color of their card frame is dark blue, similar to the border of a Ritual Monster, but with a hexagonal pattern similar to a honeycomb structure. These cards are placed in the Extra Deck.

Like other Extra Deck monsters, Link Monsters cannot exist in the hand or Main Deck (even with card effects). If a Link Monster would be moved to the hand or Main Deck, it is returned to the Extra Deck instead. If a card like "Transmigration Break" or "Degenerate Circuit" is applying, the Link Monster will be banished rather than returning to the Extra Deck.

Like other Extra Deck monsters, if a Link Monster is not Link Summoned first, it cannot be Special Summoned from the Graveyard or while banished (unless it specifies another way to properly Special Summon it).

Link Numbers and lack of DEF
Link Monsters do not have Levels, and instead have a Link Number. A Link Monster's Link Number determines either the combined number of non-Link Monster Link Materials or the combined Link Numbers of Link Monster Link Materials (or any combination thereof) required to Link Summon it. A Link Monster's Link Number is also equal to the number of Link Markers it has. A Link Monster's Link Number can be found next to its ATK, in place of the DEF on other types of Monster Cards.

Because they do not have Levels, Link Monsters cannot be used for Ritual, Synchro, or Xyz Summons (unless otherwise specified). Effects that depend on a monster's Level, such as "Gravity Bind", "Burden of the Mighty", and "Roulette Barrel", have no effect on Link Monsters.

Because they do not have DEF, Link Monsters can only exist in Attack Position, and cannot be either placed in or changed to Defense Position (either manually or through a card effect). This makes them unaffected by any cards that change battle positions, and by extension, they cannot be placed face-down as they cannot be affected by any cards that would change them to face-down Defense Position (such as "Book of Moon"). This also serves to prevent rotating the card and changing the direction(s) that its Link Markers are pointing. For this reason, Link Monsters cannot be targeted, or chosen by an effect that would Special Summon only in Defense Position (e.g. Return to the Frontlines)

Link Markers
Link Monsters also have Link Markers, indicated by red arrows radiating outward from the art frame. These indicators denote the Linked Monster's Linked Zones on the field, which its Link Markers point to. A Zone becomes a Linked Zone if at least one Link Monster's Link Marker points to it.

Fusion Monsters, Synchro Monsters, Xyz Monsters, and Link Monsters can be Special Summoned from the Extra Deck to a Main Monster Zone that is currently a Linked Zone. Monsters occupying a Linked Zone are said to be linked to the Link Monster whose Link Marker is pointing to them.

Link Summoning
A Link Summon is the act of Summoning a Link Monster from the Extra Deck using the requisite number of Link Materials listed on the Link Monster, provided that the combined number of non-Link Monster Link Materials and the Link Numbers of Link Monster Link Materials exactly match the Link Number of the Link Monster being Link Summoned. During the Main Phase, the turn player can Link Summon by sending the Link Materials from their side of the field to the Graveyard.

Playing style
Based on the cards revealed so far, Link Monsters seem to have effects based around their Linked Zones and the monsters in those Linked Zones.