2(Black Clover)

An Au where Noelle is actually Nozel's daughter(due to some woman drugging him and forcing herself on him as she wanted the prestige of being a Silva and royal) and Acier died protecting Noelle from Vanica who wanted to use Noelle for something.

No one but Nozel, Acier, Julius and the two oldest Vermillion siblings know about Noelle being actually Nozel's daughter.

Nozel tried to be a good father/brother to Noelle but he felt like it was his fault that she was targeted and his mother died so he tried to keep distance from her which lead to him not noticing how bad things were at home for his daughter.

One day Noelle run away after Nebra and Solid teased her too much and she ended up running into Jack, who while looking like he wasn't good with children had taken care of his siblings when their parents died, who helped her calm down and once he got her to open up about what made her sad, he got furious.

Jack knew Nozel could be a bitch but he had also heard how much he cared about his 'youngest sister' so hearing how much Noelle was suffering under Nebra and Solid's hands made him furious that the eldest Silva was blind to her suffering so after getting her to fall asleep and leaving her in his room at Green Mantis headquarters under the care of one of his subordinates before making his way to Nozel to have a long talk with him.

Nozel hadn't been ready for Jack to invade his office and start shouting at him but even less to hear about how his siblings had been treating his daughter, it broke his heart to notice he had been so focused on keeping Noelle away from him to protect her that he hadn't noticed that things were going against his plan.

This made Nozel decide that he had to talk with his siblings and maybe send them on a few missions that would teach them some respect and also make up to his daughter.

Nozel ended up breaking up in front of Jack(not crying, just telling him things) and told him the truth of Noelle's birth and how he felt it was his fault that Acier had died and Noelle was targeted to which Jack called him stupid as he was turning Noelle weaker instead of strong.

After this, the two formed a type of friendship and the relationship of the Silvas become much better especially Noelle and Nozel's.

Noelle still joined the Black Bulls as she wanted to prove herself instead of joining her family's squad and Jack's who she grew to see as a somewhat parental figure like Nozel.

It was only after defeating Vanica, that Nozel finally told Noelle's truth about her being his daughter and that despite her origin, she was the most precious thing she had.

Anything else(like if Jack survives, if Nozel and Jack's relationship becomes somethings more, etc) is up to the writer.