ʜᴇᴀᴅᴄᴀɴᴏɴ: ᴍᴀᴛʜɪʟᴅᴇ ( w/ @mathiiildeswann )
Kaley was first told by her father that she had a younger half-sibling shortly after the Heracles threat had been neutralised. In usual fashion, her father broke into her campus flat (he made the point of security not being the best where she was staying) and broke the news.
To say she was shocked was an understatement; especially when she found out that Madeleine Swann was her sisters mother and the last she’d heard the woman had broken her fathers heart - (which hadn’t endeared her to the then ten year old who hadn’t met the woman) - and he had gone to Jamaica and into retirement with Kaley one of the few people who knew that a) he was indeed still alive, and b) where on earth he was hiding. But, like with most occurrences with her father, Kaley had taken the news (relatively) well and the two girls had met the next day.
While the two girls initially have a stilted relationship- both having grown up with their fathers ingrained behavioural detachment; the pair eventually become close. Mathilde becomes Matti (something the younger girl initially hates, before eventually it becomes something between the sisters) and a new normal begins.
Both eventually end up working at MI6 - Kaley, after a stint working within the Anomaly Research Centre (most of her file from there is redacted even from Tanner) & Mathilde being recruited from Naval Intelligence.
When Mathilde gets promoted to 004 (beating their dads record by eight years), Tanner recommends Kaley to work alongside as her Handler. It’s.. an interesting dynamic as Kaley isn’t sure whether she should be thankful her sister isn’t as bad as their dad - or concerned about how many assets come in with well place gsw’s or broken bones.
