Empathy is the ability to feel the emotions, thoughts, hopes, desires, and dreams of others. Lydia expresses this in the tattoos she possesses.
According to a list created by Edgar, Lydia "sees what people need". Lydia appears to know the names of people painted on her back (Orientation). She was able to give out Danko and Hiro Nakamura's names after Samuel put ink onto her. It is unknown if it's the only way for her to tell names.
Fourteen years ago at the Sullivan Bros. Carnival, Lydia was said to use her ability (Stolen Fate). She saw a baby on fire in a crystal Edgar stole from a fortune teller, while Edgar saw elder versions of himself and Lydia kissing. The fortune teller claimed the crystal is "just a hunk of quartz" and "another prop"--however, she added that Lydia's power polluted it.
Lydia later reads Hiro, but tells him he needs to touch her for it to work. After reading his emotions, she has him take her back in time and he indicates that she actually caused him to do that somehow. Later, when Hiro has trouble returning them to the present, Lydia uses her ability to help him manage to teleport them back just in time. (Thanksgiving)
When Lydia decides that the Carnival needs a new leader, and that Peter would be perfect, she reaches out with her empathic powers and manages to make the compass tattoo that Samuel gave him reappear. The tattoo remains on him for at least awhile and thanks to it, he learns Samuel's true identity. It's unclear how she managed to do this as she seems to work through touch (Close to You).
At the end of her life, Lydia ended up reading someone through a kiss like Sylar did to Claire: Samuel kissed her as she was mortally wounded and dying after rejecting her reading him, allowing Lydia to tell that Samuel was behind the attack on the carnies by Eli, framing Noah Bennet for the act. (The Art of Deception)
Sylar manifests this ability after an intimate encounter with Lydia. Like her, he seems to be able to gather basic information about a person's wants and desires through touch (Let It Bleed). He later uses this to understand Claire without having to cut her head open. Sylar proceeds to kiss Claire, noting that he found Lydia's use of the ability on him hyper-erotic (Pass/Fail). He also is able to create tattoos on his skin, although he had some trouble at first.
Sylar uses this ability immediately after absorbing it by seeing through Lydia's façade and realizing that she simply wants to manipulate him. Later, after demanding Samuel to inject him with ink, he forms a tattoo of Claire Bennet on his arm, indicating that he did not truly want to be at the carnival. He seems to have some trouble creating a tattoo at first however, and was only able to make it lie still after Samuel told him not to try to control it.
- Lydia is known to have had this ability. (Orientation)
- Sylar has empathically absorbed this ability from Lydia. (Let It Bleed)