She is the third and final gynoid produced in the Iczer line by the Cthulhu, physically appearing to be ten years old, and is the younger sister of Iczer-1.
Her favorite special attack is the Iczer Bomb (イクサー・ボム, Ikusā Bomu), a powerful shoulder-charge that is capable of inflicting major damage to the enemy.
She lives on a lunar colony with her best friend Kawai Shizuka, and works part-time at a fast-food delivery service.
When Neos Gold's forces attack, she is at the Moonbase delivering food to the crew of the Queen Fuji (クィーン・フジ號, Kuīn Fuji-gou).
Nagisa later appears in the drama CD trilogy of the sequel series, Iczer Girl Iczelion.
After Iczer-3 contacts her on Earth, she inherits the powers of the living robotic armor Iczel (イクセル, Ikuseru), becoming the titular Iczelion (イクセリオン, Ikuserion).
Atros is a clone of Iczer-3 created by Neos Gold using the stolen Iczelio energy halfway through the series.
With her mother turning her back on her, Atros switched sides, choosing to think of Nagisa as her mother, and joined forces with Iczer-3 to launch a final assault on Neos' home base, and working together in concert with Iczer-3, successfully brought down the barrier around the fortress.
Neos was not about to let her creation's betrayal go unpunished, however, and launched a powerful attack against Atros, mortally wounding her.
She works with Nagisa part-time at a fast-food delivery service, and is nearly killed by Fiber when Neos' forces attack the moonbase.
Yajin is a part-time worker at the moonbase, where he helps to fine-tune the guns on the base's various warships, including the Queen Fuji.
A fifteen-year-old young man of Chinese descent, he can be quite sarcastic at times, and has lied to Iczer-3 on at least two separate occasions.
He is the sole officer in charge of the Queen Fuji's weapons systems, and is also a fairly good shot.
He becomes quite impressed with Iczer-3's strength in battle, even going so far as to gain a very rudimentary understanding of the alien technology involved in her creation.
As the series progresses, he slowly develops a romantic relationship with the captain of the Queen Fuji, Candy Barts.
In the radio drama novelization of Iczelion, she is Rob's girlfriend, and often worries about the fate of the Earth, as well as for Iczer-3's safety.
Sadly, she had to part ways with her much-beloved Nagisa at the end of the series, understanding that Earth should follow its own destiny.
She then spends the majority of the OVA recovering in a healing chamber aboard the Cthulhu ship, sending Iczer-3 to defend Earth, which Neos has now targeted, in her place.
She also holds a large soft spot for her sisters, and may even think of Nagisa Kasumi as her own granddaughter, though this is unconfirmed.
Iczer-2 is Iczer-1's evil twin sister, originally created by Big Gold in the previous OVA series specifically to kill Iczer-1.
After Atros' repeated failures to kill Iczer-3 and destroy the Queen Fuji, Neos Gold starts to realize that the only one capable of defeating Iczer-3 is another Iczer gynoid, and resurrects Iczer-2 to that end.
Later, after a fully rejuvenated Iczer-1 returns to Earth to aid Iczer-3, Iczer-2 gets her shot at revenge against her elder sister.
Though she fights with all her strength, Iczer-2 is once again defeated by Iczer-1, who decides to spare her life in the end, saying she will not let another sister fall in battle.
In the very beginning of the series, she engages Iczer-1 in an epic battle that ends in a stalemate, with both combatants exhausted and badly wounded.
In just five minutes, Neos wipes out nearly two-thirds of humanity, and reduces every major city on Earth to ruins.
However, before she can land a fatal blow, she is slain in battle by Iczer-3, thus ending the reign of terror she unleashed upon the Earth.
She is also the first opponent faced and defeated in battle by Iczer-3, who taunts her by calling her an "old lady", an insult that infuriates her.
As her name would suggest, she has the power to control any and all types of insects, and uses them as her preferred means of attack.
Using this power, she actually managed to wipe out a significant number of Earth's military forces, securing a foothold for Neos.
Her partner is a bestial android named Iota, and their combination attacks proved difficult for Iczer-3 to counter at first.