Unmarked spoilers are ahead, per Spoilers Off rule.
In episode 5, Shion explains that nothing scared him more than the thought of losing Nezumi.
Nezumi sending a message to Shion's mother, letting her know that Shion is safe.
And another one after that, promising to reunite the two of them.
Karan (little girl from West Block) wearing a very familiar-looking lilac sweater in the anime. Apparently Nezumi gave it to her after growing out of it.
Nezumi must have kept it for a while after growing out of it before giving it to Karan. She didn't believe he had ever worn it. Awww.
It's small, but the way Nezumi affectionately ribs Shion for showing her so much kindness because she has the same name as his mother.
Nezumi and Shion sharing how much they've grown through knowing one another. And making up as the sun rises. After they've exchanged punches to the face. D'awww!
Nezumi wrapping up Shion in a blanket with him to protect him in episode 9 and him protecting Shion from an attack.
Shion's mother running after Shion when the walls surrounding No. 6 have fallen. She finally gets to see her son again.
Nezumi's "good-bye" kiss to Shion at the end of episode 11. Also, a Tearjerker.
In chapter 1 of the manga Nezumi and Shion fall asleep in an adorable position. They also hold hands while laying on the same bed in episode 1.
In chapter 17 Shion threatens to snap after he sees a lot of people get killed but Nezumi grabs him and tells him not to. In response, Shion looks at Nezumi and thinks "This is where my heart is. Proof...that I am human. I was human when he stole my heart, and human when I longed to stay by his side...Nezumi...I...I want to stay human!"
