Clever men die just as quick as the rest.
Ser Grinnaux is a member of House Dzemael and nephew of the count. Ser Grinnaux the Bull is a peerless warrior. Yet while his combat abilities were exceptional, his diagreeable personality led to more than a few altercations with others.
By his twenty-ninth nameday, Ser Grinnaux had earned a notorious reputation for his brawls at the local taverns and his willingness to strike knights who questioned this judgment on campaign. It was through a drunken quarrel that he became close friends with Ser Paulecrain. Unfortunately for some, Ser Grinnaux's peerless resulted in the occasional fatality, which the Count de Dzemael would be quick to conceal with coin.
He is also a recurring boss in Final Fantasy XIV: Heavensward. He is first encountered in a solo instance battle during the quest "Divine Intervention", and latter reprises as the second boss of The Vault.
Ser Grinnaux fights alongside Ser Paulecrain Coldfire. His opponent is Alphinaud, which he captures with his Holmgang while the player has to free the unmoving Alphinaud.
Ser Grinnaux initially uses marauder techniques, occasionally, using Rive to damage players in a line. Once his health drops to 50%, he will knock everyone back as he transforms into his primal form. In this form, he uses AoE attacks in sweeping arcs, and can tear dimensional holes that inflict vulnerability up on any party member that comes near. He always uses Hyperdimensional Slash towards one party member, followed by a second in a random direction. After these two, he will eventually use Faith Unmoving to knock players back, requiring careful positioning to avoid getting flung towards the dimensional tears.
As his health drops, he will occasionally start using a Dimensional Rift attack that places a gravity orb in a circle area of effect. Those who step into it will be afflicted with Weight.