Turns out there are bosses everywhere in Elden Ring Nightreign, including the top of the castle that is normally a pain to clear out. Reddit user Aphod posted a clip showing how to scale its walls and reach the boss sitting on top,

This is a detailed boss guide for Caligo, Night of Misama in Elden Ring Nightreign's Fissure in the Fog mission.

Our in-progress Elden Ring Nightreign guide gives you a Recluse Remembrance quest walkthrough, explaining how to start the Recluse’s Remembrance quest, how to handle Recluse’s Chapter 6 challenge, and how to complete each task along the way.