Which Harry Potter film was the first to feature the character Fenrir Greyback?

Harry Potter and the Half-Blood Prince was the first Harry Potter film to feature Fenrir Greyback.

Greyback is a werewolf and an ally of Voldemort. In the film, he appears during the attack on the Burrow and is identified by his savage behavior and association with the Death Eaters. Dave Legeno played the character in the main film series.

Greyback is distinct from Remus Lupin, another werewolf in the story. Lupin tries to control the effects of lycanthropy and generally resists Voldemort, while Greyback embraces violence and deliberately seeks to spread fear through attacks.

The character also appears in the final two films, where he takes part in the wider conflict and the Battle of Hogwarts. Half-Blood Prince was released in 2009 and was directed by David Yates, who also directed the three films that followed.