Lizi, Thunderspine Tramper

Before the quest chain becomes available, you must reach Renown 9 with the Maruuk Centaur and be level 70. You also need to have completed Initiate's Day Out from the Sojourner of Ohn'ahran Plains achievement.

Once the prerequisites are met, head to Initiate Radiya at 56.12, 77.01 in Ohn'iri Springs in Ohn'ahran Plains to pick up the first quest in the chain. She is also found nearby at 56.17, 77.07 and 57.64, 78.98.

Pick up the quest 'To Tame A Thunderspine' from Initiate Radiya at 56.12, 77.01. Collect 20x Fluorescent Fluid from any insect creature in the Dragon Isles, and bring 150 Dragon Isles Supplies. After turning in, wait for the daily reset before the next quest becomes available.

Return to Initiate Radiya at 56.12, 77.01 each day after the daily reset to pick up and complete the next quest in the chain. Each quest requires 150 Dragon Isles Supplies in addition to its specific item. Items for Days 1 through 4 — such as High-Fiber Leaf — can be purchased on the Auction House if needed. Only the Day 5 item cannot be obtained from the Auction House.

For certain daily quests, you may need to purchase an item such as Meluun's Green Curry. You must pick up the relevant quest from Initiate Radiya first before you can buy the item. Ohn Meluun can be found at 57.67, 72.27 to allow you to purchase the item. A related vendor location is also at 57.58, 72.29 and 57.05, 77.65.

On Day 5, pick up the final quest from Initiate Radiya at 56.12, 77.01 first, then gather the required item. Note that the Day 5 item cannot be bought from the Auction House, so it must be obtained in-game. A tent location at 53.51, 79.07 may be relevant during this final step. Upon completing the turn-in, you will receive Lizi's Reins and unlock the mount.