Origin

For most of her adolescent life, Cassie Sandsmark was a normal teenage girl. She lived alone with her mother Helena, a respected archaeologist . Her father was absent for her entire childhood, to the point that Cassie wasn't even aware who he was.

Helena Sandsmark had begun working with Wonder Woman through a kind of happenstance, but the heroine made a quick impression on Cassie. When Wonder Woman found herself dangerously close to defeat at the hands of a clone of Doomsday, Cassie borrowed some of WW's unused equipment (notably the Sandals of Hermes and the Gauntlet of Atlas). After helping defeat the villain, Cassie continued to use he artifacts to occasionally assist the Amazonian Princess.

Later on, Cassie was able to steal a moment of Olympian god Zeus' time, which she used to request actual super powers. Zeus was impressed enough by the child's willpower and courage to grant her request. The powers came with a loophole, however: Helena has the ability to cancel Cassie's ability whenever she wishes. Thus far, Helena has allowed her daughter to continue unabated, only rarely using this ability.

Cassie soon accepted the title of Wonder Girl, and trained with Artemis, Donna Troy, and even Wonder Woman herself. She became especially close to Troy, whom she had idolized as a child (a fact that is evident by the choice of wig for her original Wonder Girl costume). It was Donna who gave Cassie the original Wonder Girl costume, a symbolic passing of the torch.

Young Justice

Young Justice

While assisting the Amazonians whenever the opportunity arose, Cassie found herself wandering deeper into the world of superheroes. After being assaulted by the villain Harm, Cassie found herself recruited by Robin, Superboy, and Bart Allen, a group of teenage heroes known as Young Justice. Along with Arrowette, Secret, and Empress, Wonder Girl represented the second wave of Young Justice members, creating an honest team out of what was originally three sidekicks goofing off and fighting crime as an afterthought.

During her tenure with Young Justice, Wonder Girl grew into a full-fledged superhero. She took over leadership of the team when Robin stepped down from the post, all while cultivating a crush on Superboy and close friendship with Secret and Arrowette. It was during this period that Cassie's secret identity was revealed to the public when she was forced to defend her high school against an attack by Wonder Woman's nemesis the Silver Swan who thought that she should be Wonder Girl.

Just as Wonder Girl began settling into her leadership role, the Teen Titans and Young Justice were offered sponsorship by a mysterious corporation called Optitron. While mulling over the pitch, both teams were assaulted by Indigo, a misunderstood android who unwittingly activated a homicidal Superman robot. Donna Troy was killed in the ensuing battle, an incident that left the heroes shattered. Depressed and guilt-ridden over the death of her friend and idol, Cassie contemplated retiring from superheroics.

The Teen Titans

Instead, she found herself persuaded to join a new incarnation of the Teen Titans, reformed from the ashes of Donna's death by Cyborg, Beast Boy, and Starfire. Wonder Girl fought alongside former Young Justice teammates Superboy, Robin, and Impulse (now going by Kid Flash), as well a de-aged Raven and new recruit Speedy. The new team came up against a litany of threats from the original incarnations past, fending off assaults by Deathstroke, Brother Blood, The Fearsome Five, and Dr. Light. She also found herself constantly confronted by the Olympian Ares, who gave her the lasso she currently uses.

While a member of the Titans, Cassie surmised the true identity of her father. After assisting Wonder Woman in defeating Hades and restoring order to the Olympian Pantheon, Cassie was granted one wish which she used to force the revelation of her true parentage -- Zeus himself. Zeus and Helena Sandsmark had a dalliance while Zeus was disguised as a human, resulting in the now half-Olympian Cassie.

Cassie also finally began dating Conner Kent, the then current Superboy. They enjoyed a comparatively normal courtship until Lex Luthor activated long-latent mind control of Conner, resulting in Superboy brutally attacking the combined forces of the Teen Titans and the Outsiders. It was Cassie who eventually returned Superboy to sanity, but the incident resulted in his leaving the Titans, and thusly his relationship with Wonder Girl.

Wonder Girl continued to fight alongside the Titans, including venturing to the planet of New Cronus to save the life of Donna Troy, until the Infinite Crisis hit. When the Olympian gods left Earth following an attack by Maxwell Lord's OMACs, Cassie found herself without her power source. She reluctantly accepted half of Ares' godly abilities, a gift from the war god in exchange for Cassie accepting him as her brother.

Infinite Crisis

As the final battle with the megalomaniacal Alexander Luthor loomed, Cassie reunited with Conner, followed by the two finally consummating their relationship. Their newfound love was not to last, however, as Superboy died heroically while single-handedly destroying Luthor's universe-generation machine.

After Superboy's death, a depressed and vulnerable Cassie found herself taken in by a Kryptonian resurrection cult in hopes of bringing Superboy back to life. She ultimately saw through the "Cult of Conner" with the help of Ralph Dibny, the Elongated Man (even if it seemed they may have stumbled onto some true results in their resurrection ceremony).

One Year Later

After regaining her senses, an increasingly violent and erratic Wonder Girl began a career as a solo superhero, tracking the Brotherhood of Evil. This search brought her to Robin's new Teen Titans team, whose membership she accepted begrudgingly. Still unable to fully cope with Superboy's death, Cassie finds herself working alongside Robin in hope if resurrecting Conner -- all while trying to control an unwanted attraction to the Boy Wonder.

Wonder Girl and Robin did share a kiss in front of Superboy's costume and Cassie ran away crying nothing came of the kiss and the attraction seems to have ended.

The Teen Titans where called on to save Raven from Bombshell who was hired by Deathstroke the Terminator to get Jericho's disk back since it held his soul.Raven used one of brother blood's spells to give Jericho a new body cleansed of the evil force that once held him in its thrall. Wonder Girl asked if Raven could do the same for Superboy but Raven said that Conner's soul had moved on into the afterlife and she could not bring him back.

The Titans where kidnapped by the Titans West and the two teams fought. It was really hard for Wonder Girl and Robin since a Superboy look a like (Match, a bizarro verson of Connor) was there and he looked just like Conner and was talking like him he even went as far as to say he was Conner.

This enraged Wonder Girl, to see someone calling himself Superboy, but the look alike seem to truly have some memories that belonged to Conner and Cassie stopped fighting him for a moment but the look alike knocked her and Robin out.

The entire team was beaten until Nightwing,Donna Troy and Flash showed up and helped defeat the Titans West.

Powers And Equipment

When Cassie first became Wonder Girl, she attempted to fight crime with the help of Amazon artifacts "borrowed" from Wonder Woman. She derived super strength from the Gauntlet of Atlas, while gaining flight and super speed from the "Sandals of Hermes". It was also during this period that she was trained in unarmed combat, largely by former Wonder Woman stand-in Artemis.

The powers granted to Cassie by Zeus were largely the same as those granted by the artefacts, but they operated at a higher level. Unfortunately, they also came with a rarely used loophole given to Cassie's mother Helena, wherein her powers could be cancelled if her mother so wished. Soon after Cassie joined the Teen Titans, she was granted the Lasso of Ares by the War god himself. The lasso gave Cassie the ability to manipulate electricity through it's enchanted fibers.

When Zeus and the rest of the Olympic Pantheon left Earth during the Infinite Crisis, Cassie realized that her powers were waning -- with some instances of total failure. In order to help defeat Alexander Luthor, Cassie finally gave into Ares, taking half of his powers to replace what she had lost. She seems to have retained her former abilities, but recent battles show her strength may have been enhanced -- a fact Cassie herself has commented on.

Personality

Cassie has displayed a remarkable amount of growth in her relatively short career. She originally took up the Wonder Girl legacy because of two opposing ideals: youthful exuberance and a strong sense of duty. Cassie's inexperience plagued her during the early stages of her career, but she always attacked situations with an indomitable sunny disposition.

Cassie's tenure as a member of Young Justice was littered with change, in both her civilian and superhero identities. She found herself with a powerful crush on Superboy, leading to new moments of indecision and dramatic fluctuations in confidence. However, it was out of these low points that Cassie truly found herself. Cassie ditched her childish original costume in favor of a more adult outfit, a sign of her burgeoning confidence in herself and her abilities. It was during this period that Cassie's leadership potential emerged, as she took the reigns of the team from Robin and led a massive strike force of young and inexperienced heroes into the team's most epic battle.

Her confidence was again shaken with the death of Donna Troy, leading to a reduced (and sometimes reluctant) role in the new Teen Titans. She still displayed the strength that had made her such a strong member of Young Justice, however, going as far as to take the lead in her relationship with Superboy and help Raven adjust to her life as a teenager.

Cassie continued as a stable, dedicated heroine until the death of Superboy and the loss of her powers. She has distanced herself from her mother and her teammates, letting her grief and the influence of Ares make her bitter and more violent. She has shown glimpses of the "old" Cassie during recent events, however, leading one to believe that her personality will right itself as she deals with her loss.