Penny Polendina/Affiliation

Ruby Rose
Penny first takes a liking to Ruby in the episode The Stray, when Ruby calls her "friend". Excited and eager to have a friend, she asks Ruby for confirmation on their relationship being a friendship, to which Ruby replies "Yeah, sure. Why not?" Although quick to call her a friend, Ruby does seem put off by Penny's excitement over it and even asks Weiss if that was what it was like when they met.

Penny admits to Ruby that she doesn't have a lot of friends, and thus appears to greatly treasure their friendship. She is also extremely protective of Ruby, going as far as to jump into a fight in her defense when she was injured in Black and White, and as seen during the trailer of Volume 2, where she pushes Ruby out the way of an incoming truck.

It appears that Penny is exaggerated for the reason that she told Ruby: she doesn't have a lot of friends. This is possibly due to her being isolated, given that she has had no time to socialize.

Weiss Schnee
Weiss runs right into Penny while chasing down Sun Wukong. She expresses skepticism when Penny says she is going to be in the combat tournament.

Both she and Yang run off after Penny arrives to talk to them while they are looking for Blake, apparently not wanting anything to do with her. It appears she has an admiration for Weiss' hair on the second day they meet.

Yang Xiao Long
Due to Penny's odd and robotic behavior, Yang finds her bizarre to the point that she neglects the pleasantry of a simple introduction until Blake reminds her. Both she and Weiss quickly run off when Penny shows up to talk to them while they are looking for Blake, indicating a lack of interest in associating with her.

The Driver
At the end of Black and White, Penny is collected by the driver of a black sedan car. The driver reproves Penny for taking risks by going out alone. This individual is unidentified but Penny refers to him as "Sir" in a subdued tone, implying that he has a strong position of authority over her.

James Ironwood
Penny is seen standing with James in the Volume 2 Opening. Their relationship, however, remains unclear.