like i feel like there is but i cant seem to fully understand the system

Feral -dragon

That should work if you input it.

To elaborate, in the blacklist, tags in the same line are "And" so a post with all tags is blocked. A - on a tag means except, so you would read feral -dragon as blacklist posts with feral, except if they also have dragon. Combining more tags is a bit complicated, this should help: https://e621.net/help/blacklist. There a a couple examples with explanations of how they work.