With Cor Noir, it was definitely not a genetic component that was passed on to his offspring (I have a gelding by him, and have met several other offspring). What I was told by Hilltop is that Cor Noir was mishandled (abused, actually) in Germany, and as a result never got over his deep distrust of people on the ground (we all know how some stallions can hold grudges…). But he was absolutely wonderful under saddle. And, I was around him at Hilltop on the ground and did not notice anything out of the ordinary. So I’m guessing that while he may have been a bit aggressive, I really think he was nowhere near the category of most of the stallions mentioned on this thread.
I was also told by a professional that goes (or at least went, at the time - although I think he still goes there) to Hilltop frequently, that Cor Noir was euthanized due to a broken leg. This person told me that one day he had been turned out in the same paddock that he usually went out in, when something spooked him. He tried to jump out of the paddock and broke a leg in the process. This professional was pretty close to the Hasslers, for whatever that’s worth…
My gelding by Cor Noir is hands down the sweetest horse I have ever met in the 26 years I’ve been involved with horses. I have never met a horse who loves people as much as he does, and he truly is the most gentle lamb. He is also always the barn favorite wherever we go. Currently there is a construction crew (full of non-horse people) doing renovations at my barn, and they keep marveling about how friendly my horse is - if they’re drilling in his paddock, he’s right there with his head over their shoulder. His intelligence and work ethic are also extraordinary. I’ve never owned a horse as wonderful as he is, and have only met a handful of other horses in my lifetime (belonging to others) that had the same kind of “spark” as he does. He is truly one of those once in a million horses, and I know I’ll never be lucky enough to have another one like him again. Maybe it sounds like I’m gushing
but people who meet him always end up saying the same things, and I have consistently heard great things about the minds of Cor Noir offspring - that they tend to be sweet and people-oriented, very curious, and very intelligent with wonderful work ethics under saddle. My horse’s full sister was a grand prix showjumper prior to her premature death last year at age 12. I trained my horse to the small tour level in dressage (first horse I’ve trained to FEI and first horse I’ve ridden the FEI movements on - that speaks volumes about his temperament!), and I hope to make it to GP with him before he is too old.
I only chimed in about Cor Noir here because you know how rumors get started on the internet, and I’d hate for there to be misunderstandings. Best thing for any prospective breeders would be to talk directly to Hilltop (as they are very honest), or owners of his offspring.