Ryzdrak by Matthew Cash
Ryzdrak, demon in human form, was cast out of Hell thousands of years ago for knowing too much. He's immortal but limited. He has spent his entire life searching for something to give him an extra edge to his powers, following cryptids and legendary monsters to no avail. A vampire bit him once and burst into flames, he managed to inadvertently prevent a zombie apocalypse by letting the patient zero get infected by him! But now something powerful has come under his radar. A shapeshifter. If he can get contaminated it will be another talent to help pass the time.