Glory of the Legion Raider is one real achievement, not a family of them. It is achievement 11180, added in patch 7.0.3, worth 25 points, and it tracks as account-wide progress. It covers exactly two Legion raids - The Emerald Nightmare in Val'sharah and The Nighthold in Suramar - and pays the Defiled Reins, which teach the Grove Defiler, the Nightmare-corrupted moose.
The honest scope. Legion shipped several raid metas and only this one carries the Legion name. On the live 12.1.0 criteria list it asks for 16 achievements: 7 in The Emerald Nightmare and 9 in The Nighthold. Trial of Valor never received a meta. The other two Legion raids sit behind their own separate achievements and are not part of this order - Glory of the Tomb Raider covers Tomb of Sargeras with 9 criteria and pays the Micronax battle pet plus the Tomb Raider title rather than a mount, and Glory of the Argus Raider covers Antorus, the Burning Throne with 11 criteria and pays the Antoran Gloomhound. Glory of the Legion Hero is the separate 26-criteria Mythic dungeon meta for the Leyfeather Hippogryph.
What the 16 criteria are. Emerald Nightmare wants Buggy Fight on Nythendra, Webbing Crashers on Elerethe Renferal, Took the Red Eye Down on Il'gynoth, Scare Bear on Ursoc, Imagined Dragons World Tour on Ysondre, Use the Force(s) on Cenarius and I Attack the Darkness on Xavius. The Nighthold wants Cage Rematch on Skorpyron, Grand Opening on the Chronomatic Anomaly, Gluten Free on Trilliax, A Change In Scenery on Spellblade Aluriel, Not For You on Tichondrius, Burning Bridges on Krosus, Elementalry! on Star Augur Etraeus, Infinitesimal on Grand Magistrix Elisande and I've Got My Eyes On You on Gul'dan. High Botanist Tel'arn's Fruit of All Evil, which used to need a full raid group, is no longer on the list.
Why this one is not a multi-week grind. The Wrath and Cataclysm metas timesaver.gg sells next to it, Glory of the Ulduar Raider and Glory of the Firelands Raider, sit behind a single hard weekly raid ID per character, so one blown hard-mode trigger costs a full reset. Legion raids lock per difficulty instead: LFR, Normal, Heroic and Mythic are independent, and every criterion here counts on Normal difficulty or higher. A criterion missed on Normal is simply retried on Heroic the same evening, which is why the whole meta can close in one sitting instead of spanning resets.
Realistic time and how it is booked. Both raids are soloable at the level 90 Midnight cap, and a specialist closes all 16 criteria in roughly 3 to 6 hours of play. Most of that time goes into the setup criteria rather than the kills - quenching 15 Burning Embers before Krosus dies, gathering Dream Essences from all four Nightmare gateways, and lining up 16 Eyes of Gul'dan to die inside 3 seconds. Hours are 2 for $26.99, 4 for $53.99, 6 for $80.99 and 10 for $134.99; the 6-hour rung is the usual pick for the complete meta, and anything longer is booked as repeat blocks at the same hourly rate.
The reward. Grove Defiler launched as a ground mount and became a flying mount in patch 8.1.5. Once the Defiled Reins are used it sits in the account-wide Mount Journal and any character on the account can summon it. US is the default region and EU has its own independent ladder. Piloted is standard, Self-play Remote adds 30%, Express adds 20% and Super Express adds 40%.
