One more page...
And here we have more references to the Tumblr Rumblr OCT Coffee comes from. Roamer and Bartender are two beings who Coffee considers imprisoned in their current state - she also considers both of them friends (if not even crushes/love interests) and has promised to help free them.
Roamer's story begins here.
And this is Bartender's and Quantum's ref sheet. The panel refers to this post by his creator.