She couldn't hear? He was use to such people. He even knew someone once who could not hear. He knew some sign language. Enough to pick up on context clues, and have a basic conversation.
He would sign, 'Fine', back to her. It was clumsy and he had to think about how to do it, but he was able to do it. He was happy that he hadn't forgotten everything in regards to it. Even if the recall was troublesome.
"Apologies. That is the best that I could do, though you seem capable of reading lips. So, if you do not mind, I believe i shall stick to verbal communication. You, of course, may converse with me in whatever manner you deem fit." He wasn't about to demand that she not use sign language, or that she stick to speaking. That would be rude. Besides, he was going for the affluent villian who hides his villany behind kindness. It did put him closer to his true personality, and he could play off inconsistencies in his persona this way.
"Though i would like to spend considerable time here. As a man who seeks knowledge where he can this place would be a remarkable and wonderous thing to explore! A simple reading nook and a place to rest is all i ask for. Through magical means i can provide myself with sustenance." By that he meant he could use mana to make bland and tasteless cubes that had the nutrients of a proper meal, and would fill him.
She pauses and blinks slowly, her gaze moving to the side as she contemplates his request. Finally, softly, she sighs and signs then; 'Very well. As long as you put everything back where you find it and don't disrupt my filing system I don't mind. The Library is a place for knowledge to be shared in the end. I am merely its Librarian.' With that, she turns and gestures for him to follow.
He's led through long wings and hallways from War, Agriculture, History, to others, they pass the Rotunda where her mahogany desk lies at the corner near some shelves, leaving a wide open room the middle. Poseidon follows her closely, glancing back on occasion to the man behind them.
Eventually he's led to her personal wing where her favorite books and items she's collected rely. From romance to science to preserved pieces of dying stars and or small butterflies preserved in a frame... this place speaks of her as a person. It appears to be what you would find in a normal Library in some modern city. A couch lies nearby with some blankets and pillows.
She turns and gestures to said couch. 'You can stay here.' She signs. 'If you require a more personal quarters, the Library can arrange it.' She hums. 'You say you don't require food or sustenance, however, if you feel inclined, I have a schedule of sorts. You're free to join me for meals.' She smiles wistfully and then turns on her heel and starts to walk past him, but pauses a moment before she signs a single name;
'Ava. You can call me Ava. What's your name?'