Brilliant Glimmershell
Quest reward from Beauty in the Deeps. A gift, found one day and saved for a meaningful occasion, should things ever turn around. Aquatic type. Each of the Nazjatar followers on Horde and Alliance grants an item once they reach level 20.
The 
Brilliant Glimmershell is a Battle for Azeroth pet awarded to Alliance players by leveling the Nazjatar follower Bladesman Inowari to Rank 20.
Guide awaiting review
Travel to Nazjatar
Head to Nazjatar and locate Speaker Utia at 38, 55.6 to access the Nazjatar follower system and begin working with your Alliance bodyguard, Bladesman Inowari.
Level Bladesman Inowari
Complete activities in Nazjatar to raise Bladesman Inowari to Rank 20 — once he reaches that rank, he will reward you with the Brilliant Glimmershell pet.
Note the Horde equivalent
The Horde version of this pet is 
Lustrous Glimmershell, rewarded by the Horde follower Poen Gillbrack at Rank 20 — unlike the Mount and Toy rewards, these pets do not cross-grant between factions, so each must be earned separately.
Tips
These pets are not cageable, meaning the only way to obtain Brilliant Glimmershell on Alliance is by leveling Bladesman Inowari to Rank 20 — it cannot be traded or purchased from the Auction House.
