Theseus Scamander

Theseus Scamander is a major character in the Fantastic Beasts and Where to Find Them. He was an Auror and the older brother of famous magizoologist Newt Scamander, whom he had a strained but loving relationship with, and the brother-in-law of Porpentina Goldstein and great-uncle of Rolf Scamander.

Background
By The Crimes of Grindelwald, Theseus was regarded as a war hero after his involvement in the First World War, and was promoted to Head Auror during the early days of the Global Wizarding War, with Theseus greatly contributing to the effort against Gellert Grindelwald. He was engaged to Leta Lestrange until she gave her life to protect Newt and Theseus as Grindelwald killed her.