My idea is a wolf-like beast found in Scotland (similar to LOTR wargs) which is intensely hostile to any person with non-Scottish direct lineage.
It would have been ridden by Scottish tribes around the 3000 BC mark (still not sure about the time period) in order to fight off foreign invaders and other creatures (like Nuckelavees for instance)
They would be contained by the Foundation on a private reserve staffed by Scottish staff. There may be some sort of inate link between Scots and the beasts. Maybe like telepathy.
This is just the start of it, I still haven't completely fleshed it out. Thanks in advance for any and all feedback I receive.
Also, if there's already a similar SCP to this, it would be good to know so I don't mistakenly steal their idea.