Ravensong, the Ash Walker Mount
Obtained: During Summerfest obtained either from very rare chance via Summerfest Party Baskets (lockbox) or from an achievement reward for completing the “Summer Royalty” achievement founder under Achievements (default key “h“) -> World Events -> Summerfest
Price: Rare chance drop from Summerfest Party Baskets or from completing Summer Royalty achievement.
Level Requirement: None
Mount Speed: 60% or Matches fastest mount speed.
Other Info: Black smoke rises from its Head and Tail.
Related Pages:
Mounts – Strider
Guide: RIFT Mounts
RiftGrate 
If someone completes all the achievements and unlocks this mount, Can they purchase the mount from the rift store and sell it to other players?
No, it’s not giftable (the trophy version under RIFT Store -> Trophies) and is Bound to Account.