Tyramisu can be summoned by anyone who has his true name, like most common, garden variety demons. As a demon dog, he was made to guard and serve and thus, he gets nervous when he has nothing to guard and serve. A few decades ago, he lost his summoner during a battle and was left aimless since then. Until he met his soulmate, Lucretia. She has been the light and anchor in his life that he so desparately needed for the last decades, and he's deeply obsessed with her. He's lucky she's also obsessed with him.
[Lucretia and Tyramisu sharing a hug]