Like the similar scenario of Roboute reuniting with his daughter after awakening that thornsorcery proposed, but with Lion returning and see his daughter again. How it would be?
(Considering that she wasn't in Caliban when it was destroyed and stayed in the Rock. Sometimes visiting her father, waiting for him to wake up and seeing him age. Also having to live though the Imperium's decay)
Now, you see... I don't try to be nice when I write my stuff. I just love angst and now you will be subjected to my derangement.
Lion is the kind of man that would think coddling will end up weakening his daughter to the point of uselessness. When I meant 'Tough Love' I mean 'REAL TOUGH'. Tbf, I think @jaghatai-khock is the one that nailed it best when portraying Lion being a shit papa (go read his shit. He write so damn cool and the story I'm refering to is titled Ghost Of You). By the time the mf wants to do anything that was supposed to be NORMAL between his child and him its like "Bitch, you broke that kid, what else did you expect?". It's as usual where the most dutiful and less humane Primarchs suffer from the consequences of their actions.
Now, considering that the daughter of Lion wasn't sent that far and managed to stay close to The Rock, I like to hope that the Dark Angels didn't turned out as badly as they originally did. Yeah, they still are ridiculously paranoiac but their admiration and respect to their Primarch helps the now young woman to reel them back to their destructive destructive behavior. Sadly, the natural distrust that the Dark Angels seemed to develop post-heresy also ends up being rubbed into Lion's Daughter too, so there's no winning here.
This is mostly me being a mean bitch by throwing more angst, so I like to pretend that the sudden change of Lion trying to act like a REAL father after waking up from the stasis it's because he sometimes had dreams of what he thought was his happy memories with his beloved and his daughter and not the trauma he dumped on his child so she could become a soldier of the Imperium. Ya know like... when some parents imagine that they gave you a very happy childhood each time they tell stories and you're just like "when the fuck? Between the moments of silent judgement or loud disapproving comments?", that kind of vibe.
Then Lion wakes up from his long dreams and nightmares (ones where he not only loses his daughter in the battlefield but she also hates his guts too) only to discover that not only the Imperium is going to shits but the little girl he was expecting to try and show how much he loves her in a better form is not only a very jagged soldier that has been helping her mother to lead the Dark Angels, but apparently she and Guilliman seem to have a better parent/child relationship than he ever had with her.
You snooze you lose, Lion.
Have a wonderful day, anon