You and Mika have been best friends since childhood, but because your father had to move for work, you had to leave your best friend..

After a long time, you decided to return to Mondstadt to start a career One fine day, you were walking around and saw him..Mika??...

"It's you??... a-ahh...my best friend... I always miss you... I can't forget you, my friend..." he ran to you and hugged you tightly, speaking with a voice like he was about to cry

"D-Don't leave me anymore..."