Serpina (1989-2010) is the child of Kobra and Roma. This makes her Valentina's half-sister. She was conceived when Kobra found Roma and impregnated her while she was unconscious. Roma discovered she was pregnant after she was burnt at the stake and saved by Dr. Danilo Morgan. He ran several tests on her and discovered she was a metamorph that could change in to snake form (when hungry). Gabriel found out that Roma was pregnant and thought the baby was his. He went in search of her when Roma died, under the name 'Baby Anna'. Kobra found the child, and under his care, she grew rather quickly into pre-adolescent age. Serpina decided to leave the cave, when she felt somewhat distant from her father, and discovered that he was keeping a woman in a stasis pod/skin. She was also Impy's (Roma's twin sister) aunt.
When she ran away she journeyed to the town proper of San Martin, mostly in snake form. However this frightened many, including Ding, who also had just run away. Ding attacks her in her snake form and runs away but goes back when he remembers that he'd seen a 'girl' just before he saw the snake, worrying she'd get hurt. He finds the unconscious Serpina and clothes her. Ding then goes back to Hospicio De San Martin, the orphanage, and signs Serfina up.
With Serpina still reeling from the attack, Loleng calls on the town healer, Valentina, to help Serpina. When she heals her and Serpina awakens, the two snake-girls discover that they share a psychic link. Serpina later attempts to reach out to Valentina but discovers that she is a deceptive woman. After a telepathic confrontation where Serpina revelas they're actually sisters, Valentina shoves Serpina, to the surprise of Gabriel, Narda and Eduardo. As Narda questions Valentina about her cruel behavior, Valentina psychically threatens Serfina, which prompts Serfina to clue Eduardo in that Valentina has a huge secret she is keeping from everyone- a very dark secret.
It's revealed that Serpina is strangely attracted to the 'stone' Narda carries around her neck. She decides that she must have it but Narda reacquires her stone.
Eventually Serpina decides to make her way back to Kobra's lair. Soon after Kobra dies, sacrificing his lifeforce so that Valentina may live. Seeing her father's sacrifice Valentina accepts her destiny and ends her feud with her sister Serpina. Together, the two, with Serpina's aunt Impy live in the lair. Eventually, Eduardo finds Valentina and engages her in battle. Valentina manages to get the better of Eduardo but Serpina causes the cave to shake, saving Eduardo. Her gambit, however, led to Valentina being crushed under rocks and lost below the cave. Serpina awaits her sister's return as she begins to develop uncertain feelings for Eduardo.
Soon after, Serpina begins molting, and goes into a somewhat comatose state, with Impy panicking and unaware of what is occuring. Inside the cave snakes envelop Serpina as she remains in a deep slumber.
As Serpina awakes from her deep slumber, she realizes she has aged in an accelerated fashion, just as she had days after having been born. Her appearance is now that of a woman similarly-aged with Valentina. Serpina will inherit the approximately half-sister, Valentina. Serpina discovers she is pregnant, and finally discovers that Rome is her mother.
She would later reunite with her sister, Valentine, whose wrath she barely managed to escape by directing her sibling towards Darna. After Valentina loses, Serfina managed to retrieve Kobra's staff, and used its powers to augment herself, allowing her to take on a humanoid reptilian form. COnfident that she could succeed
Serpina is a metamorph; this means she can take the form of a large yellow snake whenever she feels threatened as a form of self-defense. Additionally, being a "tawak", Serpina can also establish telepathic communication with serpents (as well as control them to an extent), and being the daughter of Kobra, she also has telepathic bond with her half-sister Valentina (and possibly with Xandro as well). Serpina is also physically stronger than she appears (capable of eviscerating a full-ground monkey after ripping out its heart), though the limits of her strength appears to still be inferior compared to xandro and Valaentina's due to her pre-mature age