Siphoning

Siphoning is the distinct ability of siphoners and witch-vampire hybrids to absorb or consume magic from magical objects and other supernatural beings albeit temporarily. As hybrids, they keep their ability to siphon magic after being turned into vampires which allows them to cast magic as vampires. They can also siphon from their vampirism as a limited source of power. This ability typically requires physical contact and when it is performed, it gives off a faint, red glow. While in some instances the process of siphoning has been known to cause intense pain, others have been otherwise painless. It remains unknown why this ability can cause harm.

Edward Herron
in chapter 8 of book 3, Edward fought off Katherine by siphoning the magic out of her. Rendering her a desiccated vampire. Even before becoming a hybrid, he was a powerful siphon. In many other chapters he fought Rebekah by siphoning her arm, and using magic to send her into a wall. After he found the weapon that Katherine possessed, he tried to siphon the magic from the dagger, this however was unsuccessful, and he ended up getting defeated by Katherine. After that he was confronted by Brandon who suspected he had the dagger. Unaware that he had lost the dagger, Brandon initiated a fight. Edward would get bitten by Brandon, and he would later Siphon off the magic inside of the lunar vampire bite. Days after, he would be confronted by katherine, He would begin to siphon Katherine, until she ripped out his heart. Ultimately killing him.

Grayson Schwartz
In chapter 2 of book 3, Grayson with the help of Rebekah and her team, Astrid and Aurelia would fight him. Grayson siphoned Aurelia until she passed out, unaware of the extent to his powers, he would try to siphon Astrid as well. This caused him to overextend his power, and make him absorb to much power. Effectively making him pass out. During the zombie attack, Andrew was bitten, causing his immortality to strip away from his body, killing him. Grayson made a deal with him. He would siphon the zombie bite away, if Andrew gave him his blood. Andrew gave in, and Grayson siphoned the zombie bite away. Grayson and Andrew were kidnapped by Aurelia, and August Zhen, (Lawrence Zhen s brother) Aurelia casted a boundary spell around them. Grayson began to siphon the spell away, but before he was finished august had snapped his neck. Grayson was able to siphon away vampire blood inside of Benjamin. He was also able to siphon Remus, who was a Yetzle and incapacitate him for seconds.

Trivia

 * Grayson was able to siphon away vampire blood in Benjamin
 * Siphoning has limits, somethings can be siphoned and others cannot.
 * Katherine's dagger (which was given to her by the ancestors), cannot be siphoned. When Edward tried to siphon her dagger he passed out and started to desiccate. The incantation is written on the handle however, this spell needs to be performed by the witch who casted the spell.
 * Doppelgänger's cannot be siphoned, even through they are a supernatural species, their blood nor is their body supernatural. When a siphon tries to siphon a Doppelgänger they begin to die.