This is an addon mod for both Vampirism and Boss Checklist that integrates the former's Ancient Remains boss as well as the Vampire Baron mini-boss into the latter's boss checklist interface as entries.
"How did you make this work? The Ancient Remains is a whole cluster of blocks, not a mob!" To begin with, the mod adds a fake, unspawnable stand-in entity that acts as the foundation for the boss checklist entry you see. The boss's entry is automatically marked as defeated once a player is detected to have broken the core block of the boss at the end of the fight.
"Why isn't this bundled with your other Boss Checklist addons?" This mod uses an aforementioned fake entity that is added by the mod itself. Thus, the Ancient Remains boss entry will appear regardless of whether or not you actually have the Vampirism mod installed. You wouldn't want a modpack where players would go around curiously searching for an "Ancient Remains" only to figure out later down the line that they do not even have the mod supposedly accommodating the boss installed in the first place.
