Good questions...an antagonist is an adversary, an enemy. But that is a vague definition. Are you over-thinking the problem?

Who is the main enemy of Drinly? Who is holding her back from doing what she wants to do?

So in your statement you said Drinly loves Will? Or is it Guy? Perhaps I read it wrong. Is it Guy who loves Drinly, but she loves Will? Maybe the person holding her back from her love is the antagonist. Or maybe now I'm getting confused.

Sleep on it. Think on it. See what you come up with in the morning. See if you get any comments from the crowd.