Dreadful Gladiator's Regalia is the Season 12 Mage arena set. This set is sold by the following vendors for 10,250 Honor Points:
Horde: Lok'nor Bloodfist in Kun-Lai Summit
Alliance: Hayden Christophen in Valley of the Four Winds. It contains 5 pieces. Has set bonuses at 2 and 4 pieces.
Dreadful Gladiator's Silk Handguards
Dreadful Gladiator's Silk Cowl
Dreadful Gladiator's Silk Trousers
Dreadful Gladiator's Silk Robe
Dreadful Gladiator's Silk Amice
Wearing more pieces of this set will convey bonuses to your character:
2 pieces: Haste increased by 5%.
4 pieces: Increases all damage you deal by 4%.
By obtaining parts of this set you'll increase your stats and be more powerful
Here you can buy Season 12 Mage Dreadful Gladiator's Regalia for EU or US Servers.
You'll get guide for getting Season 12 Mage Dreadful Gladiator's Regalia
