The Demi-Galba (デミガルヴァ) is the first boss of Ys VI: The Ark of Napishtim. It is part of a species known as "Wandering Calamities" to the Rehdans, which are monsters that have threatened the Rehda since ancient times. They can only be defeated using weapons made from Emel.
This Demi-Galba appeared at the Fountain of Prayer in the eastern Quatera Woods while Isha is at the fountain. Adol Christin manages to protect Isha from the Demi-Galba's attack and proceeds to fight it until it collapses. However, his Long Sword breaks in the process and the Demi-Galba quickly recovers. Fortunately, Olha and the other Rehdan warriors arrive just in time and Olha is able to finish off the weakened Demi-Galba by shooting it with an emelas-tipped arrow.