Pietro Polendina/Affiliation

Penny Polendina
Penny is Pietro's daughter and creation. He loves and cares for Penny deeply as his own daughter.

He is seen watching her match against Pyrrha Nikos in "PvP" from Atlas, and is visible shaken when she is accidentally ripped to pieces.

In ”The Greatest Kingdom”, Pietro reveals that his daughter had told him all about her time with Team RWBY, and explains to Ruby and the others that he rebuilt her after her core was recovered in Amity Arena Colosseum after making its way back to Atlas after the Fall of Beacon.

In "Worst Case Scenario" it was revealed that Pietro created Penny as the next breakthrough in defense technology, since he wanted a protector with a soul. Therefore to create Penny's Aura, he gave her part of his own, and to rebuild her takes more from him. Fearing that if the people would have Penny destroyed, it would cause the part of his Aura in Penny to be lost.

James Ironwood
Ironwood was the one who helped him build Penny. In "The Greatest Kingdom", he seems to be concern for Ironwood's current condition after the Fall of Beacon.

Maria Calavera
There has not been much interaction between them, but Pietro was the one who built Maria's prosthetic eyes after she lost her real eyes. In "The Greatest Kingdom", when she visits Pietro at his clinic, he forgot her until she has to remind him.