1. Gilles de Rais

Starting off with a gruesome one, the caster from Fate/Zero. In the show he calls himself "Bluebeard" which is partially right. His true name is Gilles de Rais, a nobleman that fought alongside Joan of Arc. That relationship explains why he acts the way he does around Sabre but not the other things he does. Well, he is also supposedly one of the people that inspired the story of Bluebeard. Besides that, Gilles de Rais was also a convicted serial killer and rapist.

2. Diarmuid Ua Duibhne

Please don't ask me how to pronounce that. We move on to Diarmuid Ua Duibhne, a Celtic hero, from Fate/Zero. Diarmuid is known for two things, his spears and his infatuation with the opposite sex. Diarmuid has a bit of an advantage with the ladies, if a woman looks at his forehead (where is "love spot" is) she will fall hopelessly in love with him. This got him into some trouble.

Diarmuid was a fighter for the Fianna in Ireland. What caused trouble is when the leader of the Fianna's wife looked at Diarmuid's forehead she fell for him and wanted to run away with him. Such activities are frowned upon and Diarmuid had to run for his life. The other thing special about him is his spears. They cause wounds that can never be healed.

3. Sasaki Kojiro

The assassin class servant from Fate/ Stay Night Unlimited Blade Works is known as Sasaki Kojiro. Kojiro was a swordsman from early Edo period Japan. He was famous for using a nodachi which is typically longer than a katana. He also used it far faster than any other swordsman of his time. He is also renowned for creating a move called the Turning Swallow Cut which mimicked the tail of a swallow in flight.

4. Atalanta

We'll move on to the archer of red from Fate/Apocrypha, Atalanta. Atalanta was a Greek hero and was a famed hunter. She was born the daughter of a king but sadly her father wanted a son and so decided to get rid of her. He abandoned her on a mountain top where she would've died if not for some divine intervention. Artemis, goddess of the hunt, saw this and sent a bear to take care of and raise the child, bears being a holy symbol of Artemis.

She later had some stories hunting a big boar. She is also quite beautiful and attracted many suitors. She decided to thin the now massive heard of young men vying for her love with a competition. She would marry whoever could beat her in a foot race, anyone that lost to her would die by her hands. After a surprising amount of foot races and subsequent murders she is eventually bested and married to Hippomenes who used golden apples from Aphrodite to win.

5. Semiramis

Finally, we'll talk about Semiramis, the assassin of red from Fate/Apocrypha. Semiramis is an odd one to talk about because she has both mythological bases and historical ones too. Historically she was called Shammuramat and was a very powerful yet stable regent for Assyria.

She made the transition from her husband's reign to her son's reign very smooth and prevented serious turmoil in the empire. In myth, she is a goddess who is considered a harlot and a homewrecker. Her primary myth is about her lusting after Ara the Beautiful, an Armenian king.

After he turns down her request to marry him she gathers her Assyrian forces and invades Armenia. Semiramis poisoned Ara which stirred up the Armenians. Semiramis dressed one of her lovers as Ara to make the people think he was alive while she tried, and failed, to raise him from the dead.