William Nadylam’s Yusuf Kama was hunting Credence Barebone during Fantastic Beasts: The Crimes of Grindelwald. When Yusuf was a child, his mother, Laurena, was kidnapped by Corvus Lestrange IV and later died giving birth to his daughter, Leta Lestrange. Yusuf’s father made Yusuf swear an Unbreakable Vow to kill the person Corvus loved most, which turned out to be his son Corvus V, who was born from a different woman. However, as mentioned earlier, Credence was not Corvus V, who had actually died as a child. So Yusuf wasn’t able to avenge his mother’s death as planned, but he’ll reportedly be around for Fantastic Beasts 3, and since he didn’t cross the flames to join Grindelwald’s groups, we presumably count on him either being one of Newt’s allies or at least not cause trouble for him.