This is something I did while at AC in 2011. Color pencil and pen on plain paper.

Rufus's unique body makeup and powerful immune system lets him basically act as a sponge for viruses and disease. He can absorb such maladies into his own body via physical contact, cleansing the patient and contaminating himself. His immune system then breaks down the ailments and he's right as rain in a day or two, depending on the severity of the disease.

The mutt is a particularly sickly individual Rufus stumbled upon during a trip to town, after wandering away from the senior alchemists. After much arguing and stubbornness on his part, Rufus convinced the others to bring him back to the enclave for treatment. He originally was supposed to be some nameless one-off character made just for this pic, but then I got rather fond of his design and started thinking about who he might be and what all he's done, and let's just say that you'll likely be seeing more of him real soon.