Fontaine's grand finale was the Arlecchino story mission where you take on The Knave, who then becomes a weekly Genshin Impact boss.
How to EASILY Beat Arlecchino The Knave in Genshin Impact – Free to Play! #hoyocreators
Confronting the fourth Fatui Harbinger is a difficult task, so you’ll need all the help you can get when battling them for loot. Here’s everything you need to know about where to find the Knave, how to unlock it, how to defeat it, and more.
The Knave boss fight is unlocked when you complete Ignis Purgatorius Chapter: Act One. After completing this quest, Knave will become a weekly boss in Genshin, where you can challenge her on all difficulties and obtain valuable materials.
After unlocking The Knave weekly boss fight from the Scattered Ruins domain, you can challenge Arlecchino on the eastern part of Mont Esus. You can either walk north from the nearest Statue of the Seven or teleport directly to the boss domain by clicking on it on the map.