The All-Devouring Narwhal is a mysterious creature not from Teyvat and is Surtalogi's pet. At some point in time, it came to Teyvat and started consuming energy from the Primordial Sea, causing Fontaine's sea levels to rise. During Furina's trial, the whale broke into the Opera Eclipse, but was fended off by Foul Legacy Childe. It is later defeated by the Traveler and Neuvillette, which causes the prophesied flooding of Fontaine.
Skirk states that when the Traveler and Neuvillette fought and defeated it, the whale was in already in a satiated state, making it much weaker. It is capable of consuming entire planets when ravenous.
