These two men were hired by the scheming Duke to protect and serve him at all costs. As seen by their expressions at the beginning of the film, they find his behavior odd. Whenever even the slightest oddity occurs, his cowardliness and irrational attitude will make him go into a panic, relying on his bodyguards to protect him. When Hans asked for volunteers to go with him to find Anna, the Duke volunteered his two men, secretly telling them to be prepared for whatever happens and to kill the Elsa if they encounter her. When they arrive at Elsa's Ice Palace, Hans tells them that no harm is to come to Elsa, but when they are battling the fierce Marshmallow, the two disobey Hans' orders and try to kill Elsa as the Duke told them to. They almost get killed themselves by pushing Elsa into an enraged state until Hans calms her down. One tries to shoot her with a crossbow until Hans intervenes and causes the arrow to fly upward, causing the ice chandelier to fall down. The guards were not seen after returning Elsa to Arendelle, likely suspended as punishment for disobeying Hans' commands, but the Duke was still seen afterwards, so his part in Elsa's attempted assassination was probably ignored, but he might have been scolded by Hans. At the end of the film, the Duke and his bodyguards were sent back to Weselton with a proclamation that Arendelle will no longer do business with them.
Originally, the Duke of Weselton was polite to Elsa, even offering her a dance at the coronation, but this was all to exploit Arendelle's riches in trade. When her powers are revealed to everyone, he is the first to call her a monster and continued to believe so, even though Anna and Hans tried to reassure him that she was not and was just scared. When Hans goes off to find Anna, the Duke volunteers his henchmen and tells them that if they encounter Elsa, they are to kill her, which they failed to do. When Hans told him and the other Dignitaries (as one of his lies) that Anna had died from Elsa's magic, the Duke showed some sadness over Anna's alleged death and was the first to say that there was no doubt that Elsa was a monster and that they were all in danger. At the end of the film, Elsa cuts off all ties with Weselton, due to the Duke's persecution of her.
Throughout the film, Hans and the Duke of Weselton were often at odds. They first interact after Elsa's icy curse has been put upon Arendelle, causing the Duke to panic and declare Elsa a monster, to which Hans disagrees with in an annoyed tone. Later on, after Hans takes control of Arendelle on behalf of Anna, the Duke is openly disapproving of the young prince's actions, causing Hans to snap and threaten the diminutive dignitary to be charged for treason, showing an annoyance of the pompous Duke. Hans, however, uses the Duke's irrational behavior and hatred towards Elsa's magic in his plot to steal the throne, telling him that Anna was killed by Elsa, which immediately has the Duke declaring Elsa a threat to the kingdom, thus allowing Hans to further his plans to execute Elsa, now that he had the necessary support.
The Duke of Weselton was polite to Anna as with her sister, and even danced with her (after Elsa told him that her sister dances) and asked her if she knew why the castle gates were shut, but she said that she did not know. When Elsa's powers were revealed, he was briefly hostile towards her, asking if she had magic powers like her sister, but Anna and Hans reassure him that she is ordinary. Anna and Hans argue with the Duke that Elsa was not a monster, but the Duke refuses to believe them. When Anna says that she will go to get Elsa, the Duke quickly agrees, showing that by this point, he was not too concerned with Anna's safety. When Hans was giving out necessities to Arendelle's citizens, the Duke showed that he did not trust Anna, believing that she and Elsa were conspiring to doom them all. But in the end, the Duke showed that he had begun to care about Anna a little as he showed grief when Hans lied to him and the other dignitaries that Anna had been "killed" by Elsa. He then said that there was no doubt that Elsa was a monster to the point of "killing" her own sister; disgusted by her alleged actions.