I don't ship Jean and Marco. They were best friends and people should respect that instead of just shipping them. Losing a friend or a lover is painful, but losing a best friend feels like a part of your heart has been ripped off violently.
Levi x Jean I don't ship them since it's obviously Levi x Me but whatever. Levi x Petra is cute too but Levi x Me is just too amazing. And anyone that read this you read the word 'me' so u kinda ship Levi and yourself, whatever ur names are