Malevolent Gladiator's Refuge is the Season 12 Restoration Druid arena set.
This set is sold by the following vendors for
The legs and hands armor also drops from Sha of Anger.
Patch 5.3.0 (2013-05-21):
Restoration PvP 4-piece set bonus now reduces the cooldown of [Ironbark]
by 30 seconds (down from 90 seconds).
Wrath of the Lich King
: Savage/Hateful/Deadly Gladiator's...
: Bloodthirsty/Vicious Gladiator's...
Mists of Pandaria
: Dreadful/Malevolent Gladiator's...
Warlords of Draenor