Dolly

 is an exclusive character and the main antagonist of Hayate no Gotoku! CAN'T TAKE MY EYES OFF YOU

Appearance
Dolly has long flowing Aquamarine colored hair and yellow eyes. She is always seen wearing a black one piece dress along with Shin's wedding ring.

Characteristics and Personality
At first, Dolly appears to have a calm, dark demeanor. However, it is revealed that she has a somewhat obsessive personality over the Kurotsubaki, going to great lengths to gain posession over it. It is revealed in Episode 11 that she desires the Kurotsubaki in order to bring back her king.

In a flashback of the Kurotsubaki's origin, a woman with an appearance very similar to Dolly is seen transferring the soul of the old king into a younger body. This implies that Dolly herself may be very old despite her appearance.

Dolly also appears to have magical powers, being able to block Isumi's spell tags, and able to manipulate plants at will.

History
Long ago, Dolly had once served a king whom she loved dearly. She helped him gain immortality by constructing a device known as the Kurotsubaki. Over the years Dolly had used the Kurotsubaki's power to transfer the king's soul into healthier younger bodies whenever the king was in need of one. However, after transferring the king's soul into the Kurotsubaki, Dolly inadvertently lost the Kurotsubaki. Eventually over the years, it ended up in the Sanzenin family's possession becoming the treasure of the Sanzenin family.

In many attempts over the years, Dolly had used novice thieves to locate the Kurotsubaki, but they all ended in failure. She eventually met a young thief named Shin Hayek and manipulated him into locating and stealing the lost Kurotsubaki for her. Some time later, Dolly eventually learns of the Kurotsubaki's whereabouts and possibly Shin's marriage to Yukariko. Dolly sends her crow to steal Shin's wedding ring, before striking a deal with him to exchange the stolen ring for the Kurotsubaki. However the exchange was never made due to Shin accidently activating the Kurotsubaki before being caught in a car accident.

Years later, Dolly finds an abandoned little girl named Ruri in the desert and takes her in. Some time later after having raised Ruri as her own daughter, Dolly informs her of the Kurotsubaki and sends her to Japan to retrieve it for her.

Trivia

 * Dolly's seiyuu, Akemi Kanda also voices Rin's Manager from the Sore ga Seiyuu! Anime. She later guest stars as herself as a member of Aice5 in Sore ga Seiyuu! Episode 11‎‎.
 * Her story looks a lot like the one that was told by Ruka in episode 7, her being the nymph that served a prince and helped him gain immortality.