Clan Calatin - The Twenty-eight Monsters (二十八人の怪物, Nijūhachinin no Kaibitsu?) is a monster who fought against Cú Chulainn during the war with Medb in Celtic legends. Medb describes it as a masterpiece engraved into her legend.
Serving under Orlando Reeve in the False Holy Grail War, Clan Calatin - The Twenty-eight Monsters (二十八人の怪物, Nijūhachinin no Kaibitsu?) is the codename of a group of magi police officers granted various Noble Phantasms created by Caster. Comprised of close to thirty men and women, Reeve felt the name suited them. They are not regular police officers, but rather a force which had undergone some special type of training. While humans would generally stand no chance against a Heroic Spirit even with greater numbers due to their immunity to physical attacks and overwhelming strength, allowing humans to master Noble Phantasms, the miraculous trump cards of the Heroes fighting in the Holy Grail War, can dictate the direction of battles to such a degree.
While they are dressed in black, prim, and intimidating police uniforms that symbol authority with handcuffs and pistols at their waists rather than clothing that would normally be worn by magi, each carries a different non-standard weapon that include a sword, bow, shield, spear, chain, scythe, staff, and musket. Their appearance makes the sight of them seem like a ridiculous group of police officers who might be going to the local Renaissance Fair, but any magi looking upon the scene would likely faint due to the power of magic and heroism radiating from the Noble Phantasms. Due to Caster's ability, the Noble Phantasms are said to possess power greater than the originals.
The summoning of Servants can be considered the "summoning of Noble Phantasms." Like the Kusanagi in the legend of Yamato Takeru, Noble Phantasms were symbols of Heroes, making them capable of maximizing the power of each individual Hero, so he believes their presence is enough to match other Heroes. He believes that Gilgamesh will be their biggest obstacle, and wishes to slay him by overwhelming him with the number of people he has at his disposal. Caster provides the means to do so by providing weapons greater than the originals, as mere forgeries would be powerless before him. He wishes to find an opening by all means, be it honorable or underhanded, before he is able to draw his Ea.