For those who have not completed Xenoblade Chronicles, this page or section may contain spoilers regarding the plot. Discretion is advised.
There are some unseen characters in Xenoblade Chronicles that are never seen in-game or explicitly named. Nevertheless, they affect the party through quests given by their surviving friends and family.
Cheryl's Son is a Homs in Xenoblade Chronicles. His name is unknown. His armour, knife, and gun can be found during Mementos of a Lost Son, after Cheryl asks you to bring her these items as a memento of her son. He was apparently killed while travelling to the head of Bionis.
Earnest's Friend is an unseen character in Xenoblade Chronicles. His name is unknown. His surviving friend, Earnest, asks the party to place some flowers on his grave by Kasharpa Falls during Earnest's Solitude. When they find the grave, an Arrogant Tirkin, the one that killed Earnest's friend, appears and the party avenges his death by killing it.
Cherri's Mother, or Cherri's Mamapon, is a Nopon in Xenoblade Chronicles. Her name is unknown. Her surviving sister, Rasha, asks the party in Avenge a Mamapon's Death to retrieve the Cloth Shred from a Pillager Hode and give it to Cherri, the surviving daughter. The party avenges the mother's death by killing the Pillager Hode and completing the quest.
Satata's Younger Brother
Satata's Younger Brother, or Satata's Little Brotherpon, is a Nopon in Xenoblade Chronicles. His name is unknown. His surviving brother, Satata, asks the party to find his keepsake, the Mushroom Cap, that belonged to his little brother during the quest Satata's Younger Brother. When talking to Dulland after he moves to Colony 9, he will explain that the brother worked with Dulland as a courier. But he was too proud of his work, and ended up getting killed by a Mechon while trying to save his delivery. The party survives the brother by tossing a part of his keepsake into the Makna Falls during the quest Rest in Peace.
During the Story
Dunban and Fiora's Father
Dunban and Fiora's Father is a Homs in Xenoblade Chronicles. His name is unknown. His surviving son, Dunban, tells Shulk in Alcamoth how he was killed by a Mechon roughly a year after Fiora was born, causing him to take the role of a father figure to Fiora.
Melia's Biological Mother
Melia's Biological Mother, or the Second Consort, is a Homs in Xenoblade Chronicles. She has been long dead before the events of the game as she was a Homs, and they have a much shorter lifespan than High Entia do. She was second wife to Sorean Antiqua, as all emperors are required to have two wives, one High Entia (First Consort) and one Homs (Second Consort). Melia tells the party in the Imperial Villa that her mother loved the place.