Only reason why this is going up her, opposed to the Commander discussion area is because it is a new keyword.
When using a "Companion" as the actual Commander, not the "101st" card, do the Companion rules still need to be followed? Asking this because I do like how a few of them are, w/ unique abilities. BUT I do not not want the limitations of only casting it once from it's "zone" and not be able to cast it from the "Command Zone."
I do not want to jump to any conclusion here, but it seams the Companion rule only applies to when it is being used as a companion... right?
Only if you designate a card with a companion ability as your chosen companion do you have to follow that card's deck-building restriction. And the chosen companion has to start outside the game (and therefore outside your deck).
In the Commander variant, if you designate a chosen companion, it doesn't have to comply with its deck-building restriction (since it's not in a deck), but all the cards in your deck (including your commander [C.R. 903.6] and cards in your deck with companion abilities) have to comply with that restriction.
A companion ability's deck-building restriction doesn't restrict you from putting cards with a companion ability in your deck or in your sideboard, or declaring a card with a companion ability as your commander, as long as all relevant deck-building rules and restrictions are followed. However, if a card with a companion ability is in your deck (including if it's your commander [C.R. 903.6]), that card's deck-building restriction is not followed because it's not designated as a companion.
The thing to remember is: Having a companion ability is not the same as being a player's companion.
With Ikoria: Lair of Behemoths, the rules for the Commander variant changed.
In the Commander variant, you can't bring a card into the game from outside it (whether by the companion ability or otherwise) if—
the card has the same name as a card in your starting deck (including your commander [C.R. 903.3]) or a card you own in the current game, or
the card's color identity includes colors outside your commander's color identity
(C.R. 903.11).
As a result, for example, in a Commander game you can't bring Gyruda, Doom of Depths into the game from outside it (whether by the companion ability or otherwise and even if Gyruda is your chosen companion) unless—
your commander's color identity includes blue and black,
your starting deck's commander was not named Gyruda, Doom of Depths,
your starting deck otherwise had no cards named Gyruda, Doom of Depths, and
you don't own a card named Gyruda, Doom of Depths in the current game.
EDIT (Jul. 8): Edited to conform to additional rule changes in the meantime.
EDIT (Jul. 23, 2021): Edited to conform to rule update with Adventures in the Forgotten Realms.
When using a "Companion" as the actual Commander, not the "101st" card, do the Companion rules still need to be followed? Asking this because I do like how a few of them are, w/ unique abilities. BUT I do not not want the limitations of only casting it once from it's "zone" and not be able to cast it from the "Command Zone."
I do not want to jump to any conclusion here, but it seams the Companion rule only applies to when it is being used as a companion... right?
Edit: Same if you run it in the 99 btw.
In the Commander variant, if you designate a chosen companion, it doesn't have to comply with its deck-building restriction (since it's not in a deck), but all the cards in your deck (including your commander [C.R. 903.6] and cards in your deck with companion abilities) have to comply with that restriction.
A companion ability's deck-building restriction doesn't restrict you from putting cards with a companion ability in your deck or in your sideboard, or declaring a card with a companion ability as your commander, as long as all relevant deck-building rules and restrictions are followed. However, if a card with a companion ability is in your deck (including if it's your commander [C.R. 903.6]), that card's deck-building restriction is not followed because it's not designated as a companion.
The thing to remember is: Having a companion ability is not the same as being a player's companion.
EDIT (Apr. 16): Edited third paragraph generally.
In the Commander variant, you can't bring a card into the game from outside it (whether by the companion ability or otherwise) if—
As a result, for example, in a Commander game you can't bring Gyruda, Doom of Depths into the game from outside it (whether by the companion ability or otherwise and even if Gyruda is your chosen companion) unless—
EDIT (Jul. 8): Edited to conform to additional rule changes in the meantime.
EDIT (Jul. 23, 2021): Edited to conform to rule update with Adventures in the Forgotten Realms.