Sense is a power that Black Remiens gain naturally as their power grows. For those who wish to learn the Black Arts could also learn this ability as well, yet it is many times difficult to learn it versus Black Remiens who are born with it. Typically non-Black Remiens will learn this ability last due to the difficulty of it. Some compare it to be as difficult to learning the Blue Arts.
The basic power of Sense is Telepathy which gains the person the ability to read people thoughts and emotion. As you advance in your skills it could improve to reading the weaknesses and strength of friends or allies. It could prove useful in battle against foes. There are even techniques Black Remiens can learn that block out others from reading their thoughts and weaknesses that could prove useful to them. Yet the higher the enemies' Sense the more challenging it is to protect against it and vice versa.