Altaïr Ibn-La'Ahad works as a master assassin for an organization called the Hashishin (Assassins) during the Crusades, in the late 12th century. Along that same time line, his future ancestor, Desmond Miles, is kidnapped by a huge corporate conglomerate known as Abstergo Industries. Desmond is then placed in a special machine, called the Animus, which uses “genetic memories” to discover secrets that only Altaïr knows.
Players are introduced to Altaïr and fellow assassins, Malik and Malik's brother, as they are being sent into Solomon's Temple to retrieve a valuable artifact. Once there, they find that the Templar Knights are not only in the temple, but have already secured the artifact. Further establishing himself as someone who feels he is above the Hashishin's strict codes of subterfuge, Altair engages the Templar group's leader, Robert IV de Sable, in open combat after breaking all 3 of the Assassin's tenets. The assassination attempt goes poorly and Altaïr is lucky to escape with with his life, leaving his fellow assassins to fend for themselves as he escapes back to masyaf, where he discovers that Malik lived and recovered the treasure, but his brother had lost his life, and malik has lost his arm. This eventually lead the Templars back to the Hashishin stronghold. Altair activates a trap among the templars, he is faced by Al Mualim and the village to face his mistakes.
Altaïr's inability to follow the tenets of the Hashishin, not to mention the instigation of an all out war with the Templars, cause him to be demoted and stripped of many of his skills and abilities. Altair must then embark on a series of assassinations to recover his lost rank, and also unravel the sinister threads that weave his world together.
Though Altaïr may come as a cold hearted and ruthless assassin, he is really fighting for what is right and just, and trying to find the truth that lies behind the world around him. Over the course of the game Altair becomes wiser and more like a master Assassin, by the end of Assassin's Creed, Altair becomes a Grandmaster of the Assassin order.
Throughout Assassin's Creed II, Ezio finds codex pages written by Altaïr. These pages fill in gaps about Altaïr's journey after the first game as he slowly comprehends the power of the Pieces of Eden. The codex pages also contain designs for new weapons such as the second hidden blade and a wrist pistol which Ezio utilises throughout his journeys. Altaïr was also able to make modifications to the hidden blade which allowed the user to keep all his fingers. Altair was also the one that decided that the Assassin order must be secret and mobile, therefore disbanding Masyaf.
If all the Assassin's tombs are explored and all seals found, Ezio is able to wear Altair's armor.
Altair made an appearance in Assassin Creed Revelations in which we see some of Altair's Lost days through seals that Ezio must recover.
Altaïr is voiced by Philip Shahbaz.
Altaïr's first name is derived from an Arabic word related to “flying” or “the bird”. His last name, Ibn-La'Ahad is literally translated from “son of none”. These two elements surface in Altaïr's character as his eagle-styled tunic and cowl and being the child of both Christian and Muslim faiths.
Born in Syria, Altair was raised to be an Assassin from his young age and has achieved the rank of master Assassin by his mid twenties. Altaïr's mother died when he was a child, and Altaïr's father Umar had been executed by the Saracens for killing one of them. His father was executed when Altaïr was only an 11 year old.
Altair was born into the order of Assassin's, not showing much compassion to his enemies and friends on some occasions. However, he quickly rose among the order of the assassins at a young age using his skills. He was devoted to the order and its interests, focusing on nothing else. Altair grew up rebellious, arrogant and overconfident, forgetting about the rules of the order and thrill of the hunt. But as Altair progresses, he starts to be wise, observant and enjoys the thrill of finding his own target as opposed to sending people to do his job for him. He learns to treasure the creed of the assassins again and perfects his abilities.
As Altair becomes Grandmaster, he questions the way of the order, particularly its tenets and free-thinking. For that, he changes it's ways to adjust, allowing poison and mobility among many things. He also puts the Piece of Eden to use to form technology way ahead of his time like the hidden gun and his armour.
During his life, Altair has fell in love twice. The first one, Adha, was killed, and Altair avenged her with his rage, swearing that he would never fall in love again. However later, he falls in love with Maria, once a templar, who he married and had a children with, two sons called Sef and Darim.