Fans are thrilled to see Deadpool & Wolverine when it hits theaters later this month. One of the film's biggest selling points is its connection to the 20th Century Fox era of X-Men films. Several returning actors, characters, and concepts establish a firm bridge between the Marvel Cinematic Universe and its previous competitor. One of the many interesting crossover moments involves a fight to the death between Hugh Jackman's Wolverine and Tyler Mane's Sabretooth. What is the grudge between these characters?