Heartwarming / My(stara's) Little Ponies: Friendship Is Adventuring

• Luna reveals in a letter to Marcus that she is very protective of the Elements of Harmony, Twilight especially, and will not stand for them being hurt in any way. (Unfortunately, this leads to Marcus spending most of the story thinking that Luna is going to kill him as soon as she discovers his identity.)
• Sweetie Belle quickly bonds with Marcus and starts referring to him as her big brother. Any scene with Marcus and Sweetie Belle interacting with each other is nearly cavity inducing.