Warlocks usually are former witches who failed to follow the "Wiccan Rede" (the witches moral code) and now hunt and kill witches to steal their powers.
Warlocks can also be born if they have at least one warlock parent.
It is also possible that a familiar turns into a warlock. Once a familiar becomes a warlock, they have until the next new moon to purge itself of its new life. If it succeeds, it becomes immortal. If it fails, it returns to its animal state for eternity.
Warlocks can blink which means moving from one place to an other with a blink of the eye. The eyes are very sensitive, flashing light can keep them from blinking.
Warlocks do not bleed.
Usually a warlock freezes or can be blown up but not always. A Power of Three spell is the only guarantee.