Noun
your foster brother is a male who is not a son of your parents but who is raised by your parents
Source: WordNetfoster-brother
A predictable yet compelling romance blossoms between Mallory and Rider, the former foster brother Mallory never expected to see again. Source: Internet
Death Alboin is killed by Peredeo while Rosamund steals his sword, in a 19th-century painting by Charles Landseer In her plan to kill her husband she found an ally in Helmichis, the king's foster brother and spatharius (arms bearer). Source: Internet
But Tessa is a fighter, having survived a rough childhood with her foster brother Brian - who has stopped by the hotel to catch up. Source: Internet
He was the foster brother of Ásgrimur. Source: Internet
However, it is said that he had a falling out with his foster brother, who ultimately killed him. Source: Internet