May is shown to have a strong friendship with her teammates and has shown to work well with them in their operations and goal of bettering Mantle.
May is shown to be highly devoted to helping the city of Mantle and has shown to greatly care for the citizens of the city. This is seen where May abandoned her life and place within the Marigold Family in order to help the people who needed it in Mantle despite the opportunity of getting a position within the Atlas Military due to being one of the top graduates at Atlas Academy.
May herself has shown that she would gladly choose Mantle over Atlas despite the dire situation of the invasion due to believing that Mantle stood a lower chance of surviving than Atlas.
As seen in "War", May harbors deep resentment for the City of Atlas due to her family, the Marigolds, having kicked her out due to not accepting her choices. This led her to develop a sense of bias when forced to choose between Atlas and Mantle, with May choosing to abandon Atlas in favor of protecting Mantle despite still having living blood relatives in the city.
May's dislike for Atlas could also have something to do with her disliking the general attitude of the Atlas Elite and their obliviousness to the hardships of the citizens of Mantle.
May's parents were the ones who disowned her after she chose Mantle over Atlas and refuses to be their son. In "War", she doesn't consider them to be her family and she doesn't care about saving them during the war of Atlas against Salem.
Henry is May's cousin. In "War", she doesn't care about saving him and she doesn't consider him to be her family. She also considers him a spare heir to the family, saying that he is to the Marigolds as Whitley is to the Schnees.
Robyn is May's leader. Like Fiona and Joana, May is shown to have a close relationship with Robyn as one of her prime supporters and teammates and faithfully follows her orders and trusts her deeply. This is shown during Robyn's victory party, where May was seen happily reassuring Robyn of her victory of the council elections and showed confidence in the righteousness of Robyn's cause and faith in her leader's abilities as a politician.
As seen during her partnership with Ruby's Team, one of May's prime motivations for assisting them is due to Robyn being excited and ecstatic at the news of hearing about the new Amity Communications Tower and her wanting to help finish it for her sake and the sake of the Kingdom.
However despite her personal feelings on Robyn, May's loyalties and sense of responsibility won't stop her from abandoning her for the greater good of Mantle. In "War", she refuses to save Robyn and Qrow Branwen who are detained by the Atlas Military due to her belief that saving two Huntsmen won't do much to help in bettering their situation in combating the invasion of Atlas.
Fiona is May's teammate. Just like for Robyn, May is close with Joanna and is protective of her. In "Risk" after Fiona breaks down in tears after Ironwood announced that he'll destroy Mantle if Penny doesn't surrender herself or if someone interferes with his plans, May is quick to hug and comfort her, before being joined by Joanna.
Joanna is May's teammate. The two appear to have a close relationship and work well together. In "Risk" both hugged and comforted Joanna after she broke down in tears after Ironwood's ultimatum.
May is willing to help Ruby to get to the terminal in Atlas Academy. In "War", she disagrees with Ruby and she refuses to save both Atlas and Mantle. This decision was partially due to her bias out of resentment for Atlas, but it is also evident that May believes that they don't have enough time or resources to spare to protect both cities during the invasion.
In "Dark", May has shown to have left the Schnee Manor and headed back to Mantle to help the people in the Crater. She would later call Ruby and hear their explanation of staying in Atlas to Help Penny and Nora before promising to try and follow her to assist in protecting Mantle, Ruby would later apologize to May due to their inability to be of any further help to her and Mantle, May seeing the massiveness of Salem's forces, tells her not to beat herself over it and has come to understand the difficulty of Ruby and her group's position and assures her that she hold nothing against them for their decision.
Although they had little interaction with each other, May was shown to be able to work together with Weiss and her team in their efforts to the infiltrate the main Atlas's Military Complex in order to get the needed credentials of General Ironwood in order to get Amity Communications Tower online.
In "War", May is shown to have a more complex relationship with Weiss. When Weiss asked May about her family in Atlas and her refusal to help them, May reveals her resentment for her family and her history with them and their apparent rejection of her due to them not approving of her personal identity nor her decision to help the people of Mantle.
Later May was shown to sympathize with Weiss due to their similar situations with their respective families rejecting them and simply replacing them with their "spares", showing a sense of kinship with her. However due to her resentment for her family and Atlas itself, May was also shown to be somewhat confused at Weiss's insistence of wanting to save Atlas despite the horrible treatment they received.
May is the one who carries the unconscious Nora in the Schnee Manor after she overused her Semblance.
She calls her "Robo-girl" before Penny corrects her and addresses her by her name.
As seen in "War", May is shown to have a negative view of Whitley and has hinted that she herself sees and considers him no better than the other Atlas Elite who cares only for themselves and their shallow desires and needs and therefore not someone worth saving. This is seen where May herself implied that she saw him as no different than her cousin, Henry.