You will find them at jewelers. Once you linked them youre able to send messages from one to another across the world. They are used here to trigger sys messages on razor, thats why theyre suitable for that job. Party or Guildchat wont work btw.
If you're still undecided on the benefits of magic resistance... This was a "naturalist" RP character for yucking it up... nothing serious. However, as you can see the spell casting mobs here will combo you from max range very fast. Most provodexxers experience a majority of their deaths this way.
With a little tact you can avoid most situations like this. Using that video as an example if you would have come into range provoking one onto another then backed off and wait for cool down then provoked the 3rd you would hardly of taken any damage.
The character in that video didn't have provoke. 70's or so of each skill Lumberjacker Store bought equipment When not farking around making a video, I had used reapers for training resistance. While that character was 'alive' (since deleted) it was lifetime top reaper killer. edit: Not sure if you can tell or not but, there were three reapers stacked directly on top of one another making 7 (I think) hence all the crazy combos.