Assassin of "Red" (“赤”のアサシン, "Aka" no Asashin?) is the Assassin-class Servant of Shirou Kotomine of the Red Faction in the Great Holy Grail War of Fate/Apocrypha.
She is one of the Servants able to be summoned by Ritsuka Fujimaru in the Grand Order conflicts of Fate/Grand Order.
Assassin's True Name is Semiramis (セミラミス, Semiramisu?), Wise Queen of Assyria (アッシリアの賢女王, Asshiria no Ken-Joō?). Born from the Syrian mermaid goddess Derketo and a human man, she was left on the waterfront by her loveless mother. She was wrapped in the warm wings of a dove, and fed with the dove's milk. Semiramis was then found and educated by the shepherd Simmas until she married Onnes, an old general; but she was then taken away by the Syrian king Ninus who fell in love with her thanks to her beautiful face. This forced Onnes to commit suicide, and after Semiramis earned the favors of the king with original battle plans, she married him and formally became queen. A few days after the marriage, she killed the king with poison, and reigned as a regent over Assyria for the next few decades. This is the oldest case of murder by poisoning in legends.
Assassin is a very enthusiastic person who indulges in luxury and "exudes a decadent atmosphere from somewhere." Since her childhood, she has studied a wide range of disciplines such as cosmetics, hairdressing, dancing, clothing, music and astronomy, and her beautiful face has captivated many men. Her passion has led her to start a war to possess a single man, and to poison her husband, the king, for politics, but her abilities as a queen are indisputable. Proof of the many expeditions she has led can be seen on walls and the Ishtar Gate. She believes it necessary for one to be superior to others and have more desires than regular people as a ruler, thinking that those who uphold frugality are only playing a sport privileged to those who have gained the "most important possession of all", authority. She feels that those who rule commit tyranny simply from the act, so those who are kings must also be tyrants.
Differing from the normal Hassan-i-Sabbah Assassins, Kairi Sisigou's first impression of her is someone whose murders were not done in secret, but all deliberated and premeditated acts brought forth from a single glance or word that would cause her targets to die by the hands of others. Saber of Red compares her to Morgan, her own mother, citing that Assassin "has the same smell." While she will play with others when she has the upper hand, she is quick to anger when a situation is not going as she feels it should, especially finding Caster of Red extremely troublesome with his actions that sometimes go against their overall plans.
Having grown up a child abandoned by her birth mother and subsequently saved by strangers, Semiramis holds her mother in great contempt. While she believes that all women will eventually arrive at the role of "life-giver", she still holds those who fall for the allure of men as weak. Likewise, she see men who claim other women without a second thought as despicable. So for her mother, who not only fell for a mortal man, but also abandoned her duty as a mother is truly despicable. However, Semiramis is not without her gratitude, for thanks to her mother, divine blood flows through her.