Intro: It only took one conversation... But that's enough for me.

Proof: Ashiya, also known as Alsiel, was the Demon General of King Satan before being transported to Earth alongside Satan/Sadou Maou. He's still Maou's humble... servant? I guess? But at least he's not nearly as evil as he used to be.

Rika is Emi Yusa's best friend and eccentric coworker from Earth. Whenever she's on screen, you can always expect a line from her asking about Emi's relationship with Maou. It is glorious. She is the captain of that ship.

Ashiya and Rika met when Ashiya was spying on Sentuckey Fried Chicken (I swear, this show...). Rika asked him about Emi and Maou, so he came up with some false story of why Maou and Emi don't particularly like each other. But then Rika spoke curiously about Ashiya's extreme loyalty towards Maou, and she tells him he prouder of himself, and not think so low of himself. Ashiya smiled and thanked her for her kind words, saying no one had actually spoken such things to him before... to which Rika responded by blushing immensely and stuttering a "you're welcome".

Emi got her revenge that day.

What I think: Sadly, that's all the proof I know of. But this ship sails on happily as I wait patiently for Season 2. *waits eternally*