Mass Effect: Andromeda introduced a whole new cast of characters with the Andromeda Initiative, and among them was a man quite obviously born to be a leader. Alec Ryder came to the Initiative with a laundry list of achievements that set him apart from other candidates, including his history with the task force that discovered and entered the Charon Relay, and his years as an N7 operative.
Alec's many achievements branded him an incredibly capable force to be reckoned with and eventually earned him a lucrative position as a military attaché to the Citadel. Unfortunately, he developed an intense fascination with human advancement through artificial intelligence that became a dangerous obsession and cost him nearly everything.
Council laws deemed experimentation and creation of AI to be illegal, but that did not stop Alec from conducting his research. Eventually, his unwillingness to let go of something he believed would be highly beneficial to the human race -- a race considered both fledgling and only moderately advanced by the other races in the Milky Way -- led to Alec's eventual dishonorable discharge from the Alliance military. It cost him his job, his resources and a large chunk of hope he carried after his wife, Ellen, was diagnosed with a rare, incurable and terminal neuro-genetic disorder.
Alec found himself seeking even more information and interviewing a Quarian historian about the Geth uprising in hopes of discerning a cause he could manipulate in an effort to change the outcome for future artificially intelligent creations. He sought out Liara T'Soni and even found himself dealing with the Shadow Broker to obtain rare information to further his research.
He came to believe the Quarians failed to integrate the Geth with organics, theorizing that such an integration fostered a symbiotic relationship between an AI and its host. He created an AI that he called Simulated Adaptive Matrix, or SAM, and pushed his superiors to go against Council ordinances, which inevitably led to his dishonorable discharge.
Despite the destruction of his career, Alec did not stop looking for ways to perfect SAM. Ellen's groundbreaking research in the field of human biotic implants led to the creation of what would become the first Pathfinder implants used by the Andromeda Initiative. Similar to the biotic implants Ellen created, which were designed to enhance electrical signals in the nervous system, the Pathfinder implant also connected to the host's circulatory system, endocrine functions and exteroceptive senses, such as touch, taste, sight, smell and hearing, as well as regulating the body's temperature.
As Ellen's condition worsened, Alec became obsessed with completing his research, sinking all of his funding into the development of a tool that could save her life. He sunk all of his financial resources into SAM, eventually depleting his life savings and arriving at a standstill that made him feel more hopeless than ever. A mysterious benefactor, whom many fans have come to believe may have been the Illusive Man, gave Alec the resources and funding he needed to complete SAM, but it was too late for Ellen.
Her illness worsened, and the couple's twins (canonically named Scott and Sara) said goodbye to their mother, believing that she died. Whether she knew what Alec did next is unknown, but before her actual death, he put her body in stasis in hopes of reawakening her once a cure had been found. After recruitment into the Andromeda Initiative, Alec stored her body aboard the Hyperion under the name Elizabeth Reilly, a secret he kept from his children.
With the Reaper threat looming over the Milky Way, the mysterious benefactor who funded the Andromeda Initiative pushed for the foundation's completion. They hoped to save as many species as possible in the event that Commander Shepard and their allies failed to defeat the Reapers. With Alec on track to become the first human Pathfinder after reaching Andromeda, he and SAM would play an essential role in pioneering the future.
Unfortunately, Alec did not survive first contact after arriving in Andromeda. After leading his control team, which included one of his children, Alec approached the control center of the first Remnant structure they encountered. After SAM and Alec activated the Remnant to stabilize the planet's atmosphere, both Alec and his child were thrown from the platform, and the younger Ryder's helmet was damaged. To save his child, Alec sacrificed himself by removing his own helmet and transferring it to them, along with the bond and connection he shared with SAM.
From the start, it's evident in the game that Alec Ryder was a man of many dark moods and secrets, so much so that his relationships with his children suffered under the weight of his obsession with AI. Throughout the game, the player character discovered a significant number of their father's memories as their bond with SAM grew stronger. Ryder came to understand that their father wasn't the man they thought he was at all, and the secrets he kept, the dealings he made, and the risks he took to secure the future of their family and the human race were darker than they could have ever dreamed.
Obsession is a mild way of putting Alec's AI research. In the end, his work had all but consumed him in ways that, even had he survived, would have taken years for his children to truly understand the sacrifices he made. Those sacrifices drew a rift between them all, despite his efforts to preserve them and their future.