When Xandrina meets Elvin, the son of General Syok and a siren, she has every reason to hate him or at least be suspicious of him. Instead, she treats him politely and is genuinely angry when she discovers he's been ordered to interrogate prisoners all night. She sternly tells Prince Wildfire to leave him be, so he could sleep.
Perhaps, even more Heartwarming In Hindsight is when Xandrina justifies her stance to Andraste, simply by saying that Elvin is a child.
Despite being an infamous war criminal and being a generally terrible person, General Syok compliments Elvin and treats his bruises after the Latlan Council beats him.
Syok has another one depending on your interpretation of him. After Elvin is attacked by Teivel, who is a vampire, Syok is the first one to run and check on him.
Another Syok one. He uses a sleeping spell on a very injured Elvin to help him sleep.
After Empress Sarai nearly kills Elvin, he becomes hysterical, and Andraste, who is definitely uncomfortable with sharing feelings, tries to comfort him.
In general, every moment between Elvin and Sunfire or Elvin and Adair is a moment of heartwarming and funny.
Adair also pays attention and asks Elvin about how he's doing when he's injured far more often than even Clare.
Andraste, Clare, Elvin, and Radiance split up to find allies to help them fight. Andraste and Clare go to Latla, a former enemy's country, and Radiance, worrying, wants to follow them and see if they're both alright. Elvin doesn't want to go, for reasons Radiance doesn't quite understand. However, since she's a duchess, she outranks him and could force him to go with her. She doesn't, leading to a truly heartwarming scene where she holds Elvin's hand and tells him that he's her friend, not just a servant.