It's random each time ... limited to the six (6) Maelstrom sets listed HERE.
Maelstrom weapons are, of course, a reward for completing the last round of veteran difficulty.
Edited by Taleof2Cities on June 19, 2017 8:29AM
"May you walk on warm sands."
"First, I would ask that you look to the poor and the suffering around Cyrodiil. Look into their hearts, and then look into your own."
"May Auri-El's light guide you in your darkest hours."