This is an addon mod for both Saint's Dragons and Boss Checklist that integrates the former's Draconian Swarm as well as the Ignivorus, Raevyx, Volitans and Atroxiia into the latter's boss checklist interface as entries.
Note that taming any of the latter four actually counts towards defeating them and will therefore check their respective entries in the checklist.
"Why isn't this bundled with your other Boss Checklist addons?" This mod adds support for the Draconian Swarm, which isn't an individual boss entity, but rather a, well, swarm of mobs that come in waves — so more akin to an event. The mod deals with this by adding a fake, unspawnable stand-in entity that acts as the foundation for the boss checklist entry that you see. The boss's entry is automatically marked as defeated the moment the player unlocks the advancement attributed to clearing the swarm. As a result of the aforementioned fake entity added by the mod itself, the entry will appear regardless of whether or not you actually have the Saint's Dragons mod installed. You wouldn't want a modpack where players would go around curiously searching for the Draconian Swarm 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.
