Abstract beings whose existence is part of the fabric of the universe itself. Or whose existence is required to maintain it, even if their function is obscure to us.

[ Even if everything they do is completely incomprehensible. ]

They are best avoided. If an Abstract has chosen to intervene or interact on a level we can perceive, you can be certain the situation is catastrophically dire. One does not want an entity capable of manipulating multiuniversal space-time showing up on one's doorstep. But there is one in particular— or a type of entity, if not the entity itself— I would be concerned about now.