Wild Seed by Octavia Butler (Patternist 1)

Doro is an entity who changes bodies like clothes, killing his hosts by reflex — or design. He fears no one — until he meets Anyanwu. Anyanwu is a shapeshifter who can absorb bullets and heal with a kiss…and savage anyone who threatens those she loves. She fears no one — until she meets Doro. From African jungles to the colonies of America, Doro and Anyanwu weave together a pattern of destiny that not even immortals can imagine.