Mythical Inspirations Behind Alexandras' Weapons
The Mystery of Nemea Shield
Cassandra's weapons in SoulCalibur II are called "Omega Sword & Nemea Shield." Of the two, the shield warrants some discussion in particular. Its Weapon Master description states that it's "most familiar and well-balanced weapon for her." Its Weapon Gallery description says that it was made from Hephaestus's holy ore and that it was once used by Sophitia, but that second part can't be true. Sophitia's weapons in SoulCalibur are called "Omega Sword & Elk Shield." In Soul Edge, she uses "Omega Sword & Owl Shield." There's not a single instance of Sophitia ever using Nemea Shield in any of the games.
After Sophitia came back from her second journey and married Rothion, the two of them went to the Shrine of Eurydice in order to to dedicate weapons to Hephaestus. While the English text says "blacksmith couple" (which is more ambiguous) the Japanese text uses the term "夫婦," which literally means "husband and wife." This means that it happened after Sophitia's and Rothion's wedding. The English text specifies that it was "a sword and shield," whereas the Japanese version does not specify the number or type of weapons, opting to use the term "武具." The next line does say that "one set of weapons has disappeared" ("一組の武具が消えているようだ…"), but this does not necessarily mean that it was the only set that Sophitia and Rothion placed in the temple.
A point of interest in this stage is the stand with slots for three swords, one of which is missing. We are led to believe that the missing sword is the one that Cassandra took. Her character profile does not mention anything about a shield, but it says that a sword in the temple reacted with the Soul Edge shard that she held. There's another discrepancy between the two different language versions in the ending paragraph of her character profile. While the Japanese version is consistent with the stage description and states that a set of weapons disappeared ("武具が一組消えていた…"), the English version says that "the holy weapon" (singular) disappeared, which conflicts with "arms" (plural) in its stage description.
The Shrine of Eurydice contains various sculpted statues. One statue featured in SoulCalibur II depicts an unknown female figure (possibly Athena ot Nike?) wielding a shield with the same emblem as Elk Shield. SoulCalibur VI contains a very similar statue (with a different hairstyle, wings added, and crown removed), also wielding a shield with the same emblem. Some other statues were probably made in likeness of Hephaestus. The bearded statue in SoulCalibur II carries a shield with the same emblem as Nemea Shield but upside down. Similar bearded statues can be seen in Soul Edge and SoulCalibur III, but the emblems on their shields resemble Owl Shield and Elk Shield respectively.
How did Nemea Shield come to be? Although the English Weapon Gallery description states that it was made from ore "received" from Hephaestus (implying that a third party was involved in making them), the Japanese description is more ambiguous. There is no "received" in there, just a statement that the ore belonged to Hephaestus. It's possible that it was Rothion who forged it, but it's not certain.
Yet another peculiarity appears at the end of Sophitia's character profile description. The game refers to her Omega Sword & Elk Shield as "new" (or "真新しい" in Japanese, which is more along the lines of "brand new"), even though she wielded them before in SoulCalibur I.
How to reconcile all of those contradictions and inconsistencies? Frankly, I don't think it's possible without disregarding at least some of the in-game information and I'm not going to attempt it.
Weapon Namesakes and The Myths Behind Them
Nemea Shield is named after a Greek city tied to two well-known myths. One of the twelve labors of Heracles was slaying the Nemean Lion:
When Hercules heard that, he went to Tiryns and did as he was bid by Eurystheus. First, Eurystheus ordered him to bring the skin of the Nemean lion; now that was an invulnerable beast begotten by Typhon. On his way to attack the lion he came to Cleonae and lodged at the house of a day-laborer, Molorchus; and when his host would have offered a victim in sacrifice, Hercules told him to wait for thirty days, and then, if he had returned safe from the hunt, to sacrifice to Saviour Zeus, but if he were dead, to sacrifice to him as to a hero. And having come to Nemea and tracked the lion, he first shot an arrow at him, but when he perceived that the beast was invulnerable, he heaved up his club and made after him. And when the lion took refuge in a cave with two mouths, Hercules built up the one entrance and came in upon the beast through the other, and putting his arm round its neck held it tight till he had choked it; so laying it on his shoulders he carried it to Cleonae. And finding Molorchus on the last of the thirty days about to sacrifice the victim to him as to a dead man, he sacrificed to Saviour Zeus and brought the lion to Mycenae.
There's not much that I find interesting about this myth. Maybe it's possible to make some sort of connection between the lion and Sophitia or Cassandra's martial prowess or hair color, but it's a weak connection at best. In the end, the lion was a wild beast slain by Heracles and Alexandras don't have much in common with it. Wikipedia also claims that there was a threat of child sacrifice or that Molorchus's son was killed by the lion, but I haven't been able to find any confirmation of this in other sources.
I think that the second myth is much more significant in the context of the Alexandra family. It's an episode in the story of Seven Against Thebes. I won't discuss the Seven in detail because the rest of it is not particularly important, but I'll give some background about Nemea itself. The ruler of Nemea was called Lycurgus. He was married to Eurydice (probably) and they had a son called Opheltes:
Pheres, son of Cretheus, founded Pherae in Thessaly and begat Admetus and Lycurgus. Lycurgus took up his abode at Nemea, and having married Eurydice, or, as some say, Amphithea, he begat Opheltes, afterwards called Archemorus.
Now as for the visit of the Seven:
Having come to Nemea, of which Lycurgus was king, they sought for water; and Hypsipyle showed them the way to a spring, leaving behind an infant boy Opheltes, whom she nursed, a child of Eurydice and Lycurgus. For the Lemnian women, afterwards learning that Thoas had been saved alive, put him to death and sold Hypsipyle into slavery; wherefore she served in the house of Lycurgus as a purchased bondwoman. But while she showed the spring, the abandoned boy was killed by a serpent. When Adrastus and his party appeared on the scene, they slew the serpent and buried the boy; but Amphiaraus told them that the sign foreboded the future, and they called the boy Archemorus. They celebrated the Nemean games in his honor; and Adrastus won the horse race, Eteoclus the footrace, Tydeus the boxing match, Amphiaraus the leaping and quoit-throwing match, Laodocus the javelin-throwing match, Polynices the wrestling match, and Parthenopaeus the archery match.
It's quite shocking how many motifs this story shares with Pyrrha's story, just with some characters and genders switched. It includes slavery, domestic servitude, as well as bad things happening to children because someone wasn't watching over them. The explanation of the name "Archemorus" is also very telling:
97. That is, “beginner of doom”; hence “ominous,” “foreboding.” The name is so interpreted by Bacch. 8.14, ed. Jebb, sama mellontos phonou, by the Scholiast on Pind. N., Arg. pp. 424ff. ed. Boeckh, and by Lactantius Placidus in his commentary on Statius, Theb. iv 717.
It sounds extremely similar to Pyrrha's tile of "Bringer of Woe" if you ask me.
New Legend of Project Soul (SoulCalibur V fan book) introduces new information about Elk Shield. Its states that its emblem depicts horns of an elk being sacrificed to Artemis. The English-language version uses the word "elk" to match the name of the shield, but the Japanese version uses the word "鹿," which might also mean "stag" or "deer" among other things (sorry for the quality of the picture with the Japanese version, I don't have access to better pics).
One myth that features deer sacrifice to Artemis is about King Agammemnon being forced to sacrifice his own daughter to the Goddess of the Hunt in order to atone for his transgressions:
But when they had put to sea from Argos and arrived for the second time at Aulis, the fleet was windbound, and Calchas said that they could not sail unless the fairest of Agamemnon's daughters were presented as a sacrifice to Artemis; for the goddess was angry with Agamemnon, both because, on shooting a deer, he had said, “Artemis herself could not (do it better),” and because Atreus had not sacrificed to her the golden lamb.
On receipt of this oracle, Agamemnon sent Ulysses and Talthybius to Clytaemnestra and asked for Iphigenia, alleging a promise of his to give her to Achilles to wife in reward for his military service. So Clytaemnestra sent her, and Agamemnon set her beside the altar, and was about to slaughter her, when Artemis carried her off to the Taurians and appointed her to be her priestess, substituting a deer for her at the altar; but some say that Artemis made her immortal.
This myth ties into another. Clytemnestra is angry at Agammemnon for sacrificing their daughter and bringing home a younger concubine called Cassandra. She conspires with her lover to murder both of them and usurp the throne. She's successful, but her son Orestes avenges his father's murder by killing Clytemnestra in turn, for which he's viciously persecuted by Erinyes, (also known as Eumenides or the Furies). In the end, a trial is held over his fate. It concludes in his favor:
After Agamemnon had returned to Mycenae with Cassandra, he was murdered by Aegisthus and Clytaemnestra; for she gave him a shirt without sleeves and without a neck, and while he was putting it on he was cut down, and Aegisthus reigned over Mycenae. And they killed Cassandra also.
But Electra, one of Agamemnon's daughters, smuggled away her brother Orestes and gave him to Strophius, the Phocian, to bring up; and he brought him up with Pylades, his own son. And when Orestes was grown up, he repaired to Delphi and asked the god whether he should take vengeance on his father's murderers.
The god gave him leave, so he departed secretly to Mycenae in company with Pylades, and killed both his mother and Aegisthus. And not long afterwards, being afflicted with madness and pursued by the Furies, he repaired to Athens and was tried in the Areopagus. He is variously said to have been brought to trial by the Furies, or by Tyndareus, or by Erigone, daughter of Aegisthus and Clytaemnestra; and the votes at his trial being equal he was acquitted.
"Protection of Eumenides" is mentioned in Pyrrha Omega's profile in New Legends of Project Soul:
Orestes is ordered by Apollo to go to the lands of the Tauri and bring back a statue of Artemis in order to atone for his crime. There, he meets his long lost sister Iphigenia and they return back home together:
When he inquired how he should be rid of his disorder, the god answered that he would be rid of it if he should fetch the wooden image that was in the land of the Taurians. Now the Taurians are a part of the Scythians, who murder strangers and throw them into the sacred fire, which was in the precinct, being wafted up from Hades through a certain rock.
So when Orestes was come with Pylades to the land of the Taurians, he was detected, caught, and carried in bonds before Thoas the king, who sent them both to the priestess. But being recognized by his sister, who acted as priestess among the Taurians, he fled with her, carrying off the wooden image. It was conveyed to Athens and is now called the image of Tauropolus. But some say that Orestes was driven in a storm to the island of Rhodes, . . . and in accordance with an oracle the image was dedicated in a fortification wall.
It's really easy to draw a parallel between the ending of this myth and the ending of SoulCalibur V, even the home city of the protagonist is the same.
Cassandra breaks her sword and shield between SoulCalibur II and SoulCalibur III. She comes back to Greece and Rothion makes new ones for her: Digamma Sword & Nemea Shield. These are also made from divine ore. Even though the shield's name is unchanged, it's a different shield. It's oval-shaped and not circular and pink instead of blue, but the shape of the emblem remains the same. Digamma ("Ϝ") is an extant letter between epsilon and zeta in the Greek alphabet. It fell out of use during antiquity, so it was already archaic by the 16th century. Although no longer used as a letter, it retained its value as a number. In the traditional Greek number system, each letter is assigned a numeric value (α = 1, β = 2, γ = 3, etc.). Digamma has the numeric value of 6. Using a letter that isn't even a letter anymore cements Cassandra's status as an "odd" holy warrior whose legitimacy remains ambiguous, unlike the 24 ones whom Hephaestus spoke to and who received weapons named after proper letters.
Another Greek symbol with the number value of 6 is called "stigma." Stigma is a ligature. Ligature is a result of two letters blending together in handwriting until they become a single symbol. In stigma's case, those two letters were sigma followed by tau. It started to look similar to digamma and was also adopted for the value of 6 during the middle ages:
The other system was to take the first nine letters of the alphabet for the units, and the rest for the tens and hundreds, disused letters being still retained for numeration, viz., ϝ, digamma, for 6, which in its early form appears as ϛ or 
, and afterwards, in the middle ages, becomes 
, like the combined σ and τ or stigma;
Handbook of Greek and Latin palaeography; Thompson, Edward Maunde p. 104
Patroklos's original weapons are called "Stigma Sword & Arcadia Shield," which means that there's a thematic connection between his sword and Cassandra's. These are the last weapons that Rothion helped him make before he died. Rothion claimed that they were made from the holy ore, but the wording in New Legends of Project Soul makes it seem like he may have lied about that. The Arcadia shield bears the same emblem as the Elk Shield. Arcadia also happens to be the place where the mythical Orestes eventually died:
and having come to Mycenae, he united his sister Electra in marriage to Pylades, and having himself married Hermione, or, according to some, Erigone, he begat Tisamenus, and was killed by the bite of a snake at Oresteum in Arcadia.
Reading all of this and considering it as a whole, the inspirations are quite obvious to me. Almost all of it ties into SoulCalibur V in some way. I think it's possible that Sawako Natori researched the namesakes of Sophitia's and Cassandra's shields while writing the scenario.