Semiramis's powers and abilities
As the world’s oldest poisoner, Semiramis uses poison as her weapon.[4] The rank of her Agility and Presence Concealment is low for an Assassin, however, thanks to possessing the Double Summon skill, she actually has the traits and abilities of the Caster class as well.[5] Having lived during the Age of Gods, she is knowledgeable in magecraft and does justice to her history as a witch. At the beginning of her initial engagement with Astolfo she nonchalantly says "she knows a little," which is an understatement.[12] In fact, it is noted that she could probably put up a good match against Karna, with the strength of her mysteries.[13]
Assassin's summoned Primeval Serpents
Semiramis' main armaments are chains and the like from her wedge-shaped magic circles. Semiramis can also summon Mystical Beasts.[3] She displays the ability to form the scales of the Sacred Fish on her hand as a means of defense, though Achilles is able to break through this version. In the anime adaptation, she can summon a shield formed from the scales to defend others, such as when she protected Avicebron from Chiron's arrow. She was even able to block Clarent Blood Arthur, though it broke afterward. Her skills with poisons allowed her to recreate the Greek Hydras venom for Chiron. She is also capable of producing magical traps in the form of chains, which Ruler must actively break.
Skills
Class Skills
Presence Concealment (C+ Rank): Hides one's presence as a Servant. Suitable for spying. The rank of presence concealment drops considerably when preparing to attack. However, this condition does not apply to poison something.[1][3] By combining her Presence Concealment and her poisons, she was able to easily slip a hypnotic drug into the tea of all the Red Faction's Masters allowing Shirou Kotomine the opportunity to manipulate them.
Territory Creation (EX Rank): Creates an area that is advantageous to oneself as a magus. By gathering specific materials, it is possible to create a "Hanging Garden", superior to a "Temple".[1][3]
Item Construction (C Rank): Allows the creation of items that carry Magical Energy. Semiramis specializes in poisons, so she can't make any other types of tools.[1][3]
Personal Skills
Familiar (Dove) (D Rank): Allows the use of doves as familiars. They can be directed by thought alone, without the need for a contract.[1][3] She has spread them throughout the entirety of Romania to act as a network of scouts to carry messages and collect information. Taking pieces of paper in their mouths, they can locate their targets, deliver the message, and immediately leave upon completion. They can track down magical energy sources, especially those possessed by Servants, allowing them to keep track of their locations any time upon entering the country.
Double Summon (B Rank): Grants the Class Skills of both the Assassin and Caster classes. An exceedingly rare trait possessed only by a select few Servants.[1][3]
Divinity (C Rank): Semiramis was the daughter of the Syrian fish-goddess Derketo and a mortal.[1][3] Simiramis displays the ability to form the scales of the Sacred Fish on her hand as a means of defense. Although one single thrust from Achilles' spear was strong enough to pierce the scales with ease, the barrier was strong enough to stop his attack. However, Achilles claimed that if he really wanted to, he could have put his spear through her scales, her arm and Shirou Kotomine's head, to which Shirou replied “Yes, I suppose you could have."[14]
Noble Phantasm
Hanging Gardens of Babylon
Semiramis most powerful Noble Phantasm is the Hanging Gardens of Babylon. Because this Noble Phantasm is "vanity" itself, the conditions for its activation are strict. It is necessary to gather a fixed amount of a very specific type of soil and stone and the entire process takes at least three days. As the name suggests, it manifests as an "enormous fortress hanging in the air".[1][3] Within it, not only are all of Semiramis' parameters increased one rank,[1][3][12] but a plus modifier is added to her attacks when she is attacking.[1][3] On top of that, whereas her fame level is also boosted to the highest class,[1][3] all other Servants who enter her domain will have their own fame reduced to zero.[15] Within the Hanging Gardens, Semiramis' power and Authority is truly absolute,[16] making her as powerful as a Ruler.[17] She would not only be able to restrain even Karna with just a single wave of her hand,[16] but she also seemed to believe that her own power alone would be enough to take down Vlad III in his Legend of Dracula form.[15] It is noted however that Semiramis would fare poorly against Jeanne d'Arc. From the beginning, the parameters of Semiramis and Jeanne weren’t even comparable. Additionally, magi had fatally bad compatibility with Ruler. Even without using a Command Spell, she could immediately defeat Semiramis.[15]
Hanging Gardens' main defensive mechanism
The gardens also possess extremely powerful defensive functions that consist of EX Anti Army magical beam attacks that step into the realm of True Magic,[12][18] and that would to make someone like William Shakespeare run away barefooted.[5] Their destructive power is compared to that of a dropped bomb,[15] or a meteor falling from the sky,[18] and even the Saber class which tends to have the highest Magic Resistance wouldn’t be able to just shrug it off.[15] A single blast was sufficient enough to knock out both Astolfo and his Hippogriff, although thanks to his Luna Break Manual Noble Phantasm, which grants A-rank Magic Resistance, Astolfo wasn’t all that wounded by the damage he took from her blasts and the fall.[12] Jeanne d'Arc was able to block it with her flag thanks to her Magic Resistance being ranked EX.[15]
Sieg claimed that by his third transformation he would be able to put up a fight against the defense functions of Semiramis' Hanging Gardens of Babylon, saying that he could likely survive the attack even if he wouldn't lose outright. Sieg could accurately calculate the power of the beam attack which Ruler had blocked, and he was confident that he could overwhelm and beat it with Balmung. However, they had learned from Astolfo that the Hanging Gardens had eleven interception spells prepared and ready for Semiramis to fire at any time. If the spell that Ruler had blocked was a ‘one’, then it was basically multiplied by eleven when fired in combination. Even then, Sieg probably wouldn’t lose, but he wasn’t confident that he could defeat it either. The odds were likely that it would turn into a contest of power—clashing against each other with all their might and merely resulting in both of them exhausting themselves.[13] Sieg and Avicebron note that attacking the Hanging Gardens with just Achilles' chariot and Astolfo's Hippogriff alone would be quite difficult.[17]
Sikera Ušum
Semiramis other Noble Phantasm is Sikera Ušum. A Noble Phantasm that can only be invoked at the throne of her fortress. When this Noble Phantasm is invoked, the magecraft Semiramis uses is granted a "poison" attribute. Heroes who possess legends where they withstood poison will receive a bonus to their resistance against this Noble Phantasm whereas on the other hand, if they have an episode where they died to poison, the damage is doubled. Different types of poison can be selected as well. In regards to the image, the poison's appearance manifests as chains.[1] Furthermore, when Semiramis is within the “Hanging Gardens of Babylon: Aerial Gardens of Vanity”, she can even summon creatures of the Phantasmal Species if they have an anecdote related to poison, such as the Bašmu. If she were summoned as a normal Assassin without the skill “Double Summon”, Semiramis wouldn’t be able to use the “Hanging Gardens of Babylon”, so she would use this Noble Phantasm as her main weapon instead.[19]