I recently started playing Anima: Beyond Fantasy and encountered a term not explained much in the book, Gnosis is a value which comes up in summoning as a restriction on what you can and cant do to some beings. so Im wonder what in the world is Gnosis? How is it determined and what else does it impact?
You will find most info about it on p276 of the core book. It is roughly a measure of how supernatural you are.
Normal people have 0, PCs start at Gnosis 10. You start having special advantages and powers at Gnosis 25.
It is supposedly fixed at birth and cannot be increased - although there are ways, including the Chimera spell of the Creation school (p130).