I think it's clear they can be put under your control during a scenario, but the modified deck-building restrictions seem to indicate that you cannot include story allies from scenario to scenario because they are usually described as "does not count towards that investigator's deck size" as is the case with Lita in Night of the Zealot
Update: AHL was too damn costly, with only Stratos and Mist being targets (ain't nobody gonna summon Bubble off AHL), Avarice gives the deck more longevity
Promethean Princess, Bestower of Flames is a prominent link monster that can destroy a monster the opponent controls as well as the user when a monster is special summoned to the opponents field
Chesnaught V 015/195 NM Ultra Rare Silver Tempest Pokemon Card Free Ship 1 Available Mint Sword & Shield Base Set $2.00 (approx
How to play: online edition If you dont have any friends you can beg, bribe, or beat into playing Magic with you, there is another, far easier option: the games online version, Magic: The Gathering Arena