Lillian Luthor

Dr. Lillian Luthor is a scientist, the leader of Project Cadmus, the mother of Lex Luthor and adoptive mother of Lena Luthor.

Early life
Lillian always favored her biological son Lex over her adoptive daughter Lena, as she consider the first one a genius and the latter nor even a "real Luthor".

Leader of Cadmus
After her son, Lex, was sentenced to 30 life terms in prison, Lillian interrupts any contact to her adoptive daughter, took over Project Cadmus, a secret lab that studies aliens, and severed its relationship with the government to usit as a mean for her personal vendetta against aliens of all kinds.

When John Corben was shot by Lena and left near death, Lillian took him to Cadmus and, as he regained consciousness, she told him that she could kill him with one click but also make him survive, John agreed, and Lillian injected liquid kryptonite in his veins causing his eyes to cloud over. The woman says that now it will be called "Metallo". After Metallo woke up he was struck by his newfound power and asked the woman who she was, to which she replied: "merely a Doctor". She then introduced him to Cadmus and explained their anti-alien mission, which he hastily sympathized with. After that she gives him the mission to kill Superman and Supergirl. Later, despite the resistance of one of her subordinates, she ordered to turn him into another cyborg.

Lillian Luthor supplied whit alien weapon Chet Miner's gang to allarm public opinion, spreading fear and discontent over the population. The next evening Miner called the woman and told her that, as people are afraid of these weapons, he had fulfilled his part of the bargain and his next move wuold be to attack Lena Luthor's charity evening to make money. However, she warn him that if they attack Lena, she would not support them. After Miner is arrested he started to told Detective Maggie Sawyer who gave them the weapons but, suddenly, he heard Lillian's voice into his head, his ears began to bleed and he fell dead to the ground alongside the other two gang members.

In the evening she comes to Lena office at L-Corp apologizing for having missed her evening and Lena asks what she can do to help her.

Capturing Mon-El and Supergirl
Few days later a bunch of Lillian's agents captures Mon-El and deliver him to an hidden base of Cadmus, putting him in a cage. Later, she told Supergirl at a special frequency that they have Mon-El and promised to kill him if she did not come. When Supergirl arrived in Cadmus, she met the real Hank Henshaw, revived as a cyborg, who was able to overcome her and imprison her in the cell next to that of Mon-El. Later Lillian revealed herself to Supergirl and threatened to kill Mon-El, if she does not deprive herself of solar energy with the help of a special device; Supergirl was forced to agree, then Lillian slapped her and took her blood before to sent her back to the cells, not bothering she and Mon-El later managed to escape thanks to Jeremiah Danvers.

Medusa
After having sent Hank to stole a sample of the Medusa virus from the Fortress of Solitude, Lillian begins to release it to kill all the aliens in National City. Later Lena contacts her and says she whant to join forces with her to release the deadly virus on Earth to wipe out all alien life. However, Lena had no intention of releasing the virus; she rendered it inert via a critical ingredient, and alerted the police about her mother's crimes. Lillian only realized she'd been double-crossed when the missile carrying the virus exploded sending only red rain falling on National City. Before she could react, the police swarmed in and arrested Lillian for attempted mass murder and other Cadmus-related crimes.

Personality
Lillian is shown to be very much like her son, Lex; cold, self-righteous, unstable and delusional in her views. Blaming Superman for her son's imprisonment, while completely in denial of the horrific actions Lex performed and his own choices, she has come to develop radically-driven disdain for aliens of all kinds. Viewing them as a poison to Earth, beings who are subtly taking control of the planet by making humans worship them, she is determined to purge Earth of these otherworldly-forms.

She is shown to be rather hypocritical, willing to kill bystanders, the very people who she claims to be trying to save, in her personal vendetta. While arrogant in her views and believing herself the true savior of the planet, Lillian is apparently a very shrewd and cunning woman. Able to anticipate how her enemies will act, she is able to plan several steps ahead and manipulate their actions.

However, Lillian's arrogance makes her short-sighted, as she doesn't realize when a member of her own family is manipulating or deceiving her; when her adoptive daughter, Lena apparently joined forces with her to release a deadly virus, only to double-cross her leading to her arrest.

Abilities

 * Genius-level intellect/Expert scientist/Leader: As a scientist Lillian has a genius level intellect, as she was able to create cyborgs synthesizing kryptonite as a weapon and even to reproduce the Medusa virus from a sample.
 * Indomitable will: A driven and determined person, Lillian is nearly fearless and always calm in every situation, as evidenced by not being intimidated even when menaced by a gang of men armed with alien technology or at the time of her arrest.