Dear RPGPundit,
I need some clarification about how to establish a mental link.
Scattered in the book there are pieces of information that, in my opinion, do not look coherent.
It's understood that via eye contact or physical touch a link can be established: this is clear.
But in Enchantment you write about the ritual of mental contact with some words to be spoken: is this a ritual specific to Enchantment?
Yes. If you have Enchantment, you can make mental contact with someone without having to either touch them or have direct eye-to-eye contact. It's a special feature of having Enchantment.
In Advanced Scrying you say (Block Scrying) that if a person as an Ego lower than the Scryer, he is not even aware of the link. Is this true only in this case? Because I've found no evidence of this in other parts.
Yes. It is only true in this case. It's a characteristic of this specific trick in Advanced Scrying.
Under Ego Conflict you say that a mental link can be established through powers, but the only power that seems to allow this is Scrying: or do you mean that Enchantment can do it too via this ritual of mental contact?
Yes, exactly. In theory, there could be other powers or items that could establish mental contacts too, but those are the ones in the game.