The Servant's True Name is Captain Hendrik van der Decken (ヘンドリック・ファン・デル・デッケン船長, Hendorikku fan deru Dekken Kanchō?), captain of the infamous Flying Dutchman. He is cursed to wander the seas forever, only being able to come on land once every seven years, and not being able to dock at the same place twice unless it has been so long that the place's name has changed and no one living there remembers him.
The Captain has the appearance of a silent but strong sea-faring man with wild black hair and unshaven beard.
The Captain's personality seems to be stoic and quiet, but his shoulders did slump slightly when his Master brought up how he once again failed to find a wife and could try again when they dock in seven years. When summoning his Noble Phantasm he breaks his usual stalwart demeanor to bellow out a sea shanty while his ship appears.
Decken and his Master, Ahasuerus had made port at the Akihabara Ward of the Mosaic City. Hunted by Kundry who deems him her lover, Erice Utsumi escorts the Master-Servant pair to the docks for them to make their escape.
Having made their way to sea, Decken summons his legendary ship, the Flying Dutchman at the behest of Ahasuerus' Command Spells which promptly destroys Kundry's gremlins before leaving the city for good.
Decken's Noble Phantasm is the ghost ship tied to his legend, the Flying Dutchman. A curse had made him the Wandering Dutchman, unable to dock on land for seven years which will be spent at sea. By the same concept of "wandering", Decken is able to dock anywhere in the world, even ports protected by powerful protective barriers, once every seven years.
As a Noble Phantasm, the Flying Dutchman has the appearance of an enormous galleon from the Age of Discovery. The galleon is equipped with three dark masts from which crimson sails are flown. Its quarterdeck is described as intimidating and fortress-like over a pitch-black hull.
Manifested along with the ship are pale wisps that coalesce into the spirits of the Captain's undying crew, forced to wander forever just like their captain and his ship. The crew will mercilessly cut down the enemies of the Flying Dutchman with cutlasses like the pirates of old.