Canon scope: Leadership of Black Meridian. Keep relationships and status specific to the period being described.
Joker leads and recruits for Black Meridian. He builds a network of capable people rather than assembling an interchangeable mob. His chief advantage is knowing what someone wants and recognizing how that desire might draw them into his plans. The warmth of an offer and the leverage behind it can be difficult to separate.
The faction's organization matters. Queen of Spades, Knight of Hearts, and Two of Diamonds are among its key operatives. Their different responsibilities and loyalties should remain visible instead of being flattened into Joker's subordinates.
Joker's weapon is a combat fan. Fan-based fighting and battlefield manipulation are established elements of his approach. His detailed technique names, costs, power ceiling, and complete ability demonstration still need consolidation from the visual-development material. No unapproved powers should be added to make him appear more dangerous.
His definitive visual design is held in the visual bible. The fan and his card-derived leadership identity must carry through future descriptions.
Jin'var has worked with Black Meridian for a long time before bringing Alaster to its hideout after the Black Briar rescue. That working relationship is established; its precise factional status must still be described according to the story era. Do not import later affiliations into Episode 1.