The Carbon Dog is the guardian of the last Your Sanctuary location. It is known as the Fire Spring. Later in the battle, this creature will change into the Diamond Dog. This is because of all the heat melting him together into a diamond. This changes the appearance into a rainbow-like, hard-cased substance.
While he is the Carbon Dog, he is vulnerable to PSI Freeze. Once he becomes the Diamond Dog, he loses all weaknesses, and gains higher stats. He casts Shield β over himself in order to send back attacks launched.