Frankensteiny

Frankensteiny (フランケンシユタイニー, "Furankenshiyutaini") is the second guardian ghost of Faust and is also his dead pet dog.

About
Frankenstieny was the pet dog of Johann Faust VIII, and Eliza Faust, who was with them ever since their first marriage. Whilst never mentioned specifically, the dog apparently died at the age of four. some point in the past, however, It has ever since been with Faust in its skeleton form, constantly wandering with him. It made its first debut during the 1st round of the Shaman Fights where it was following Faust around. Later when Faust was attacked by the Icemen and destroyed his wheelchair, he revealed that he used the bones of Frankensteiny as a replacement for his missing legs and that it can be completely revived with a little amount of Furyoku and give Faust great jumping power.

O.S. Frankensteiny
O.S. Frankensteiny Description: After giving up his legs to Eliza, Faust was confined to a wheelchair and became unable to walk for the rest of his life. However, after training with Kyōyama Anna he learned how to Over Soul the bones of his dead pet dog into a pair of legs.
 * Shaman:Johann Faust VIII
 * O.S. Type: Spirit Type
 * Spirit Ally: Frankensteiny
 * Medium Used: Skeleton Remains of Frankensteiny

This is done by splitting the bones up in the middle of the spine, so that the front legs are attached to his left leg and the back legs are attached to his right leg, both of them being attached with the spine. When first shown this seemed to put some strain on the bones, but has not been addressed since.

Anime/Manga Difference
In the anime series, Faust never loses his legs to Eliza, and Frankensteiny is never seen walking around, therefore, he is only seen briefly in a flashback in Episode 15.

Trivia

 * His name is a play of the name Frankenstein, a monster who was stitched together with dead corpses and reanimated them with the power of lightning.
 * Frankensteiny's breed is a Manchester Terrier.