Darth Talon is a red-skinned Twi'lek Sith Lord of the One Sith and one of the two Hands of Darth Krayt, created by John Ostrander and Jan Duursema for Dark Horse's Star Wars: Legacy. She first appears in Legacy #2 (2006).
No fall to narrate
What distinguishes her from almost every other Sith in the franchise is that there is no before. Talon was taken as an infant and raised inside Krayt's order; she has never held any other loyalty and has nothing to renounce. The comic uses her to make a point the films rarely get to: an order that lasts long enough stops needing to recruit.
Design
Duursema's design — crimson skin, black Sith tattooing worked across the whole body and lekku — is one of the most recognisable things Dark Horse produced in the 2000s, and it has outlived the comic it came from by a considerable margin.
Cade Skywalker
Her function in the plot is to be the instrument turned on the protagonist, and her most consequential scene is the one in which she attempts to make him a Sith rather than kill him. The series is at its best when it treats her as competent rather than decorative, which it mostly does.
Canon status
Star Wars Legends, filed here under the editorial Legacy of the Force bracket because Legacy is set roughly 130 years after the Battle of Yavin, past the end of the official era labels.