[Gallagher]

If we assume it really is from Death himself, then yes, most powerful, nothing can really compare. But, looking at it logically, it's a wood that's used in other cases, and a core that's used in other cases (albeit more rarely). Unless that story is absolutely, without a doubt, 100% true (because you know people are super amazing at keeping truth through the years), then there really is no argument anyone can make. But if for just a second we consider that maybe there's a little wiggle room... All I have to say is that had to be one HELL of a tree, and one HELL of a thestral.

As for the dragons, they are powerful, hard to control, and therefore considered dangerous, yes. But they are also perfectly able to be kept and bred. They HAVE to be contained and kept track of to maintain secrecy, but that only begs for incidents and prejudice to build up. If not for all the force, dragons would be perfectly content having nothing to do with people. On the other hand... Kelpies are supposed to actively hunt them, right? That strikes me as a huge difference right there. Huge, and very important.