From Portals of Phereon Wiki

A learned skill that can't be passed on. The MC can gain it by choosing the Tamer profession at the start, and there are a few unique characters that have it. Otherwise you will have to hope that a wild character you can recruit will have it, there is currently no way of acquiring it for your characters in the game.

This increases the chances of taming Creatures using a Net, which means you don't need to damage them as much as you would without it.