Beatrice

Beatrice (ベアトリス) is a mage of Re:Zero. She is one of the greatest wizards, if not the greatest, residing in a room with magic books only to be accessed by portal magic through doors

Plot
Beatrice is the one who heals Subaru after the first arc when the first reincarnation loop is over. Also, she can use all elements of magic, especially the Yin. She was traumatized by her past, hence, she loves to pet Emilia's Spirit Cat.

Trivia

 * Beatrice is a name derived from the French name Béatrice, which came from the Latin Beatrix, which means "she who makes happy."