Eli Vance

Doctor Eli Vance is a brilliant physicist and researcher, who is an African-American man apparently in his late fifties or early sixties with short grey hair, a beard and moustache. He wears a prosthetic leg to replace his left leg beneath the knee, which was lost when he was attacked by a bullsquid while helping Dr. Isaac Kleiner climb over a wall into a Combine city. He is presumably a graduate of Harvard University; his shirt has "Harvard" partially obscured on it but clearly shows the university's shield.

He is the father of Alyx Vance. His late wife, Azian, also lived on the premises of Black Mesa, but died in the aftermath of the resonance cascade.

According to in-game dialogue from Half-Life 2, Dr. Vance was the first human being to make peaceful contact with the Vortigaunt species, quickly persuading the alien race to ally with humanity against the Combine invasion of Earth.

Half-Life
At the time of Half-Life, Vance was employed at the Black Mesa Research Facility, working in the Sector C Anomalous Materials laboratories, and possibly also in the Lambda Complex teleportation labs. As a full-time employee of Black Mesa, he lived in the facility itself with his wife Azian Vance and their young daughter Alyx. Although he was never named during the game or featured as a full character, he is seen on two occasions in the game. He is first seen when Gordon is making his way into the test chamber – Dr. Vance and another scientist voice their concerns that their computer equipment is being damaged due to the heightened strains of the morning's experiment. When the experiment goes wrong, a resonance cascade rips through Black Mesa, causing heavy structural damage and opening cross-dimensional seams, filling the facility with bizarre creatures from Xen. When player character Gordon Freeman retraces his steps through Sector C, he encounters Vance and the scientist he had been with earlier, who is now badly injured. Vance informs Gordon that the telephone network has broken, and sends Gordon up to the surface to seek help. His last act in Half-Life is to operate the retinal scanner that starts Gordon on his long quest through the facility.

Half-Life 2
The survivors of the Black Mesa Incident, Eli, Alyx (now a young woman), Dr. Isaac Kleiner, and Barney Calhoun, form the core of a resistance movement against the Combine who have taken over Earth after a conflict dubbed the Seven Hour War. The Vances have established a makeshift laboratory, dubbed "Black Mesa East," on the outskirts of City 17. There, Dr. Judith Mossman assists them in their continuing research in the field of teleportation. Kleiner and Vance briefly establish a working teleport system between their two labs; the system fails on its second attempt due to outside influence, forcing Gordon to travel over land to reach Black Mesa East.

When Freeman does arrive at Vance's lab, his arrival triggers an invasion by Combine forces, who had been chasing him throughout. The soldiers capture Vance and take him to Nova Prospekt, a Combine-run prison near City 17.

Gordon and Alyx storm Nova Prospekt, fighting off hordes of Combine forces to locate Eli and Mossman. During the final siege, however, Mossman teleports herself and Eli into the Citadel, a monolithic structure that serves as the Combine's base.

While infiltrating the Citadel, Gordon and Alyx are captured; Dr. Breen addresses both Vances and Freeman in his office with Dr. Mossman at his side. The game does not make it clear if Mossman was a double agent the entire time, or turned on Breen when he stated that he would teleport Eli to a hostile dimension. Mossman, apparently having feelings for Eli, would have then realized her mistake. This is one theory though, as the game does not make it clear. Mossman stays with Eli to protect him while Alyx and Gordon pursue the fleeing Breen; from the couple's attitudes towards each other, it appears that Eli and Judith may start a relationship.

Half-Life 2: Episode One
Eli appears again in Episode One, having escaped the Citadel along with Mossman in one of Dr. Breen's escape pods, eventually making their way to a Vortigaunt camp outside the city. He is seen at the beginning of the game in a monitor transmission with Dr. Kleiner, telling Alyx and Gordon to get out of City 17 before the Citadel's reactor core explodes.

Half-Life 2: Episode Two
Eli is at White Forest(complete with a new argyle sweater), a resistance base, working on a rocket with Dr. Kleiner and Dr. Magnusson, which will neutralize the portal storms, and prevent the Combine from drawing reinforcements through a dormant superportal. When Gordon and Alyx arrive, they deliver a recording of a transmission from Judith Mossman, which apparently never made it to White Forest. Eli is visibly shaken by the danger Mossman is in, and was only prevented from going after her himself by pressure from Alyx and Dr Kleiner. When the Aperture Science research vessel "Borealis" appears in the transmission, Eli immediately wishes it destroyed, lest the events of Black Mesa repeat themselves. Alyx delivers a (subliminally implanted) message given to her by the G-Man, to "prepare for unforeseen consequences." After a moment of extreme shock, Eli appears to dismiss the message, asking that Alyx make him tea in another room.

Once Alyx has left, Eli explains that he too is aware of the G-man's existence (the first character in the Half Life universe to openly do so). He indicates to Gordon that the Xen crystal that began the events of Half-Life was delivered by the G-Man, and that Alyx's survival in Black Mesa was due to his interference. Moments after Gordon entered the Black Mesa test chamber, the G-Man warned Eli to "prepare for unforeseen consequences". He is convinced that the current warning relates to the "Borealis", and seems to take it seriously despite his resentment over the way in which it was delivered. Eli indicates he can reveal more about the G-man, but before he can do so, Alyx re-enters the room, and the conversation is halted.

In a scene just before the game ends, Eli is killed by a Combine Advisor while Gordon and Alyx watch helplessly. His last wish was to destroy the Borealis at all costs. Alyx then weeps over her father's dead body, as the screen fades to black, and the credits roll. The reaction to Eli's death from the other characters is yet to be seen, in Episode Three.

Other facts
Originally, Eli Vance was intended to have no relation with Alyx, but instead to be a man named Eli Maxwell, who had a scrapyard that he used as his lab rather than Black Mesa East. Alyx's father was meant to be Captain Vance, the leader of a rebel group. Both characters, however, were eventually merged to become Eli Vance.

In Half-Life, Eli can be killed 2 different ways. Either the player can return once they have the crowbar, and kill him, or they can lead Eli into the next room, where bolts of energy hit the wall. If hit a few times, Eli will die.