“The Tournament” is a big side quest that takes place in the second half of Assassin’s Creed Shadows ’ main story. It’s very rewarding, and will get you new weapons, XP, Anomaly completions for the Animus, an achievement, and a mastery unlock for Yasuke’s Kanabo and Naoe’s Tool tree:

Shadows is Ubisoft's most successful game in the franchise by a Japanese country mile, ranking high in both sales and player counts.

Worldwide, Shadows has reached more than three million players so far. Shadows had the second-highest day-one sales revenue for any Assassin's Creed game, only trailing Valhalla. Shadows did beat Valhalla by one measurement, though, setting a record for the most day-one digital revenue on the PlayStation Store for the Assassin's Creed franchise.