Background
Pietro during the "Penny Project"
Prior to the start of the series, Pietro became a scientist and a doctor in Atlas who had once worked with Arthur Watts and other Atlesian scientists in a project issued by Ironwood to advance the kingdom's defenses. Looking inward, Pietro discovered a way to transfer his Aura into a robot under the "Penny Project", thus winning the challenge and having made himself a daughter: Penny Polendina.
RWBY
Watching the Vytal Tournament
Witnessing her daughter destroyed by Pyrrha
He is first seen briefly watching the Vytal Festival match between Penny Polendina and Pyrrha Nikos in "PvP". When Penny is destroyed by Pyrrha, he reacts with restrained emotion, gripping his chair tightly. Following the Fall of Beacon, he built Yang Xiao Long's new prosthetic arm before it was sent to her.
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Helping Mantle
Meeting Ruby's Group in Mantle
Pietro is described by Maria as "one of Atlas' finest minds" that works with the Kingdom of Atlas on its technological projects, having been the one to build her prosthetic eyes and adjusting them every decade.
Upon arriving in Mantle, Maria Calavera took Ruby's Group to Pietro's Pharmacy and introduced everyone. There, he explained his business in the city; aiding the citizens by providing them prosthesis. Pietro informed them he had heard of the team through his daughter, Penny. After the Creatures of Grimm attacked the city, Pietro and Maria watched as Ace Operatives captured the Huntsmen.
After Ironwood and Ruby's group came to a mutual understanding over each other's actions, Pietro was tasked with upgrading Team RWBY's and Team JNPR's weapons and armor, fitting each new addition to the individual's needs. He also repaired Yang Xiao Long's broken prosthetic, providing a new model.
After Tyrian Callows frames of Penny during a massacre at Robyn Hill's election party, Pietro's daughter returns to his laboratory for comfort. Ruby Rose talks with Pietro about Penny's recovery from the trauma of the party. Pietro states that the footage of Penny was taken from previous incidents of her around Mantle. Pietro says that whoever was responsible for the fall of Beacon would be able to break into Mantle, but that Atlas has been upgraded. Weiss Schnee asks who might be able to break into Atlas, to which Pietro replies that it would include systems Weiss points out would be controlled by the Schnee Dust Company. Pietro expresses his concern about Penny; Ruby states that if she's dismantled, she can be reactivated. Pietro however reveals that Penny's Aura is in fact part of his. He even states if the people of Mantle get their wish to have Penny destroyed, he won't be able to bring her back with his current remaining Aura. Ruby reassures and promises Pietro that they will find the culprit.
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Fallout with Atlas
Joining Ruby's Group
After Watts turns off the heating grids in Mantle, Pietro is present in helping citizens find refuge, offering his laboratory as a safe space from the incoming Grimm onslaught. Pietro returns to Atlas, where he and Maria help Ruby's Group escape the city after their relationship with Ironwood turns sour, joining the group himself.
- Episodes Covering These Events