Renfield is a resident patient in Seward's asylum and he was diagnosed a 'zoophagous maniac' or carnivorous madman, ingesting insects and spiders, believing their life-force would prolong his years. He is also quite crafty and displays a superior intellect when he is not in a melancholy state or a fit of rage. He has a cheerful or positive outlook on life, despite being in harsh circumstances. He has great physical strength and is morbidly excitable. There's always a method his madness.