Yelena finds a kid on the first Thunderbolts mission after the events of Thunderbolts*. Grieving the loss of her sister, Natasha, she takes the child in, giving her the chance to be a sister again. Except this time, she needs to be the responsible one. The older sister. But despite all of the Red Room training that Yelena received, she had not learned responsibility. She was not good at caring for others. At trying to be the person that others could lean on. Yelena was inexperienced in the art of parenting/being a sister, but she knew a few things. She must clothe, feed, and shelter the child. Make sure they get to places on time. And she must be there. Even when it was hard. Even when she thought she couldn't do it. Because she had someone to live for now.