The control of the monsters, including the monsters in the Extra Monster Zones, does not matter in creating Extra Link, as long as they are "a series of Co-link connecting both Extra Monster Zones".
All monsters that make up the Extra Link, and any additional monsters co-linked with those monsters, are considered to be Extra Linked.
It is possible to create an Extra Link using fewer than five monsters by co-linking them diagonally, resulting in a "V" shaped Extra Link.
Controlling both Extra Monster Zones
Normally, each player can only use an Extra Monster Zone at a time. But when both Extra Monster Zones have been bound together, a new monster can be summoned to the other! Extra Link!!— Varis, regarding the advantage of Extra Link
Normally, a player can only use 1 Extra Monster Zone at a time. However, if a player would Summon a new Link Monster to an Extra Monster Zone, and the Summon would create an Extra Link even if the player has already controlled one, it is legal.
The following are the cards that mention Extra Linking in their card text:
|Japanese name||Primary type||Secondary type||Attribute||Type||Level/ Rank||ATK||DEF|
|Iron Knight of Revolution||Link Monster|
|Sanctity of Dragon||Link Monster|
|Topologic Gumblar Dragon||トポロジック・ガンブラー・ドラゴン||Link Monster|
- ↑ Advanced Link Monster Tactics: What Does “Extra Linked” Mean?
- ↑ Yu-Gi-Oh! VRAINS episode 44: "Prisoner of Destiny"