Manipulate the emotional ties of others
- "Chelsea can influence the emotional ties that people feel toward one another either by strengthening their bonds or breaking them apart."
- ―Entry on Chelsea's gift
Chelsea has influence over the emotional ties between people in the sense that she can both loosen and secure these ties. She can make partners turn away from one another, disband covens and friendships, but also can strengthen the bonds that bind one person to another.The effects of Chelsea's power are long-lasting and fade depending on how long a person has been exposed to it before separating from her. Someone could a bond (or lack thereof) to someone for decades or centuries before Chelsea's gift starts to wear off. Bella described Chelsea's power as a fluttering pressure against her shield when she unsuccessfully tried to bind some of the Cullen witnesses to the Volturi.
When the Volturi (specifically Aro) invite a vampire to join the guard, Chelsea makes the vampire feel bonded to the Volturi. This makes it extremely difficult to refuse any offer from them. Chelsea is also very important when the Volturi are in a fight, as she separates the allegiances between covens so that the Volturi can defeat them more easily. She also binds the relationships within the Volturi, allowing them to perform more effectively as a group. If Aro likes a specific vampire in the guard, Chelsea binds their ties to Aro, instead of all three of the Volturi leaders. Renata, Corin, Jane, and Alec are examples of this. Because of her gift, Chelsea is a permanent member of the guard and wears one of the darkest cloaks along with Jane and Alec.
Chelsea cannot as easily influence the emotional ties of people when those ties are stronger than just friends or acquaintances. For example, she could not have changed the way Edward and Bella felt about each other, and she also was not able to break Eleazar's bond with Carmen when he decided to leave the Volturi. Her power is also mental, as proven when she tries to bind Bella, Edward, Benjamin, Zafrina, and Kate to the Volturi during the conflict in Breaking Dawn, but is unsuccessful due to Bella's mental shield. Eleazar also suggested that abstaining from human blood allows vampires to form deeper bonds that Chelsea can't break, though this was never proven.Since Aro has kept Marcus, who could sense the emotional bonds of others instead of influencing them, it is possible that Chelsea's power only involves manipulating and not recognizing the bonds first hand.
It is not known if Chelsea could influence people while she was human, but according to Carlisle's theory that every vampire brings their most powerful trait over when they are changed, she may have been able to.
Elliot is able to create false feelings of love and admiration between people, effectively drawing them to each other.
Elliot has used the gift on a few members of the British Coven
Elliot can only create relationships between people, he can't manipulate these bonds further