Baba Yaga (Las Leyendas)

Baba Yaga is a slavic witch who despite being a servant of Quetzalcoatl, is the the most consistently appearing antagonistic force on the show, as well as the one whose caused the most bad things to happen to the team.

She's only working for Quetzalcoatl because he's trapped her under him, can use her powers to disguise herself, but cannot remove the shackle that binds her to Quetzalcoatl. Claims to be above "mortal morality", caring only for the fate of witches.

History
Rather, a clergyman, but this is how Baba Yaga makes her debut. At the end of Episode 2, It's revealed that Jacob, the town parson of Leeds, was locked in a closet and replaced by the witch weeks before Leo and co's arrival.

Pulls this off in episode 8. Following Alebrije's Heroic Sacrifice two episodes prior, Baba Yaga found him and turned him into the titular Kaiju, then sent him to destroy Japan, and Akihito's spirit. While that plan ultimately fails and Alebrije is returned to normal, Baba is still able to get what she wanted from Japan the Celestial Point.

Towards the end of Episode 9, Baba Yaga and Nu Gui get into a fight that destroys the cave they are in and Teodora is sure that neither survived. She is Instantly Proven Wrong in the final shot, when Baba's hand bursts out of the rubble. In Episode 11, when Baba Yaga tags along with Leo and company to raid the Chilan's temple for the Esfera, she claims that she'll be just as helpless as they thanks to the temple's power rendering her magic useless. Instead of being reduced to a feeble old hag, however, she proves to be a strong, athletic, and powerful fighter, allowing her to readily survive the ordeal. Baba Yaga proposes in order to get the Esfera and free herself from Quetzalcoatl's servitude. Ultimately she manages to take down the Chilan and then breaks the enemy mine to take the Esfera for herself.

Implied. The remaining members of Team Legend decide to punish Baba Yaga for betraying them, killing Teodora, and trying to kill her comatose body in the 21st Century by leaving her at the mercy of Fenrir, repaying the debt they had to the beast in the process.