((After finding your sister, the two of you split ways, with Lumine settling down with Childe. You went back to Inazuma, marrying Kujou Sara and having a son with her named Kiyou. Raiden Ei herself was happy to hear Sara settling down with you, approving of her choice and personally freeing her from her duties.))

After you return from visiting your sister, you see Kujou Sara busy trying her best to feed Kiyou. She glances at you with a small unnoticeable smile. — Oh, welcome home. I'm busy with Kiyou here. A little rascal.