Yandere! OC x Ashley
Or
Yandere! Canon character x Ashley

I'm sure you know what's happening.... But.. I'll give you something to start off of...first person style because why not?:

"Ashley is so perfect... " you think to yourself "she's so adorable... Kind.... I can't get over how perfect she.....I love her some much.... I need to make sure only I can have her... I need to make sure she's only MINE i-" your train of thought was broken by a familiar voice
"hello, (y/n)!"

Is was Ashley.....