Alenko is a trained, experienced Alliance Marines officer with a superb track record, and presumably holds a special forces qualification (N6 ?). Though he’s a trained rifleman and shock trooper, he specialises in providing frontline support to assault specialists rather than shooting stuff up.

The primary source of support is provided by his mind - Staff Lieutenant Alenko is a powerful biotic. During much of his career he was cautious about using Mass Effect fields on enemies, but after seeing the bodies of civilians massacred by the geth on Eden-Prime he became more violent and willing to blast the opposition - which in turn made him even more powerful. Though his brain is wired with the old, unsafe L2 implants Alenko is more powerful than the vast majority of biotics with L3-generation implants. From the dialogue, it seems that Alenko achieved some of the highest spike outputs ever produced by a human biotic.

Alenko is also technically-minded, and was trained as a combat engineer specialising in electronic warfare. As explained in the main Mass Effect article on writeups.org, he can use his specialised omni-tool to sabotage equipment and communications, shut down weapons through overheating, disrupt kinetic shields, etc. Between this and his telekinesis, Lt. Alenko can plunge the enemy into disarray, making it much easier for the weapons specialists to move in for the kill.

Kaidan prefers to fight armed with a pistol - presumably, he needs a free hand to use his omni-tool and to direct his biotic fields.

During an early scene Alenko sits next to Joker in the cockpit of the Normandy - this writeup assumes that he can help the pilot a bit with plotting courses. Perhaps he’s training to become a crude backup pilot in case the helmsman and the navigator are both incapacitated.

Staff Lieutenant Alenko is considered one of the rising stars of the Marine Special Forces. His association with the superstar of MARSOC, Staff Commander Shepard, dims his own light - but it also allows him to develop his skills and biotic power at a rapid pace. Though the Alliance has lost Shepard to the Council, they’ll gain somebody who can replace her when Alenko returns to serving Earth.

History

Two years after the discovery of the Mars alien technology cache, a transport ship carrying Element Zero experienced catastrophic containment failure above Singapore. There were several such accidents during the 2150s, presumably because the extraordinary properties of Element Zero and how it interacts with energy were still poorly understood.

The quantities of Element Zero any given Singaporean was likely to be exposed to were tiny - but pregnant women had breathed Element Zero particles, which ended up as small nodules within the body of developing embryos. Nearly 30% of children born in the months that followed the accident had cancer, and by 2158 it became clear that about 10% of all exposed children were presenting some unprecedented characteristics.

By 2160 it had been determined that these children could direct bioelectricity through the tiny quantities of E0 in their body to produce small Mass Effect fields. This phenomenon was called biotics.

Free your mind

A corporation called Conatix Industries moved first, and presumably negotiated an exclusive contract with the recently-formed Systems Alliance to study the phenomenon. Conatix was allowed to recruit children affected by the accidental exposures, and studied their abilities and how to develop them.

While humans biotics could only produce small effects, the idea to use cybernetic implants to increase the amounts of energy (and possibly the amount of E0) quickly presented itself. The first generation of implants, the L1, was developed in 2163 but was basically useless since biotics were too poorly understood.

Little Kaidan Alenko, whose mother was in Singapore during the accident, was among the children who joined the Conatix research program. For security and secrecy reasons, the program was established on Gagarin Space Station, more popularly known as “Jump Zero”. Gagarin is at the termination shock - the point where the Sun’s wind slows down to subsonic speeds, often considered the edge of the solar system. Jump Zero was previously used for faster-than-light flight research, but had presumably been decommissioned when the Mars discovery opened completely different, and much more promising, avenues of research.

Officially, the Gagarin research facility was renamed “Biotic Acclimation and Temperance training program” by Conatix but the kids soon called the sterile, regimented, isolated station “Brain Camp” by comparison with a military boot camp.

Brain Camp

Conatix wanted results quickly, but with the failure of the L1 implant the research with the kids was taking too long. However, during the First Contact War, alien soldiers had been observed using biotics, and Conatix contracted turian mercenaries to serve as instructors.

This was done in utter secrecy - though the Turians considered the First Contact War to have been a minor clash at the periphery of Citadel Space, Humanity was still up in arms about them. Turian biotic training saved years if not decades of research, but most of the mercenaries viewed humans as annoying primitives and were military veterans with a taste for harsh discipline. They tended to mistreat and insult the human children.

The first generations of human biotics grew up in Brain Camp constantly probed and poked by scientists - and disciplined and ran ragged by turian taskmasters. Furthermore, many of the kids had serious physical and psychological issues from Element Zero exposure, and the prototype biotic amplifiers they were implanted with - the L2 model - had numerous nasty side effect. The attrition rate is unknown, but Kaidan mentioned numerous kids experiencing severe nervous breakdowns and some dying.

It was Kaidan, then aged 17, who shut down Brain Camp. When the senior turian instructor, Commander Vyrnnus, roughed up an exhausted girl Kaidan had a crush on, the young man snapped and got into his face. A scuffle ensued, Vyrnnus slashed Alenko with a knife, and the Human reflexively unleashed a massive telekinetic blast that slew his taskmaster. This was the highest power level ever demonstrated by a human biotic, but Conatix had to shut down BAaT as both the Alliance and the turian mercenaries became quite irate.

The teenager whom Kaidan had wanted to protect was horrified by the fight and Vyrnnus’ death. Young and sheltered, Alenko was hurt by the rejection and became wary of displaying his power lest people fear him. This would slow down his development as a biotic fighter until his early 30s.

Slan

Though the first generation of human biotics had been treated like child prisoners and Guinea pigs, Alenko was comparatively lucky - he didn’t develop brain tumors from Element Zero nodules in his tissues and his L2 implant didn’t trigger serious medical complications, though it left him with nasty chronic migraines. Biotics of the L2 generation were largely left to fend for themselves no matter how bad their health was, and forced to register with both their government and the Systems Alliance as potential dangers.

Activist movements formed, many wishing to form biotic communes to be free from discrimination and mistrust. A few L2 biotics would become terrorists, fighting to obtain reparations from Conatix and the Systems Alliance. Others biotic activists and their allies investigated the various accidental E0 releases over population centres, and came to the conclusion that most accidents after 2162 had been engineered by Conatix as they were running out of subjects from the late 2150s accident. Though the activists couldn’t prove their accusations and lacked credibility due to social stigma, they made an objectively compelling case.

Between these accusations, the death of Commander Vyrnnus, Conatix’s reckless abuse of children in BAaT, a lack of oversight of the Systems Alliance on their contractors, etc. the Alliance ended the contract with Conatix. Research into biotics was transferred to the military - specifically the Systems Alliance Naval Command - though many of the private contractors retained by the military were thinly disguised Conatix departments.

This is my rifle

Knowing that he would be registered and watched all his life in any case, and wanting to see the world and be helpful, Alenko enlisted. The Systems Alliance military was always interested in biotics, and Alenko turned out to be an excellent recruitment for them — powerful biotic, top-notch technical scores, and an excellent soldier with superior command potential.

Alenko’s career is undocumented in the game, but one assumes that he was assigned to an Alliance Fleet right away. He received his commission and, by 2183, was a Staff Lieutenant.

His capabilities and track record led to his assignment to the SSV Normandy SR-1 — about the best promotion he could hope for. He had been selected by a legendary Marine Special Operations officer, Captain David Anderson, known for hand-picking the best. Alenko was further placed directly under the command of Anderson’s XO, the famous war heroine and special operations maven - Staff Commander Shepard.

Alenko would run the Normandy’s small marines detail day-to-day, but his main job would be to be on Shepard’s shore operations team. The last member of their three-man MARSOC fire team would be a young Corporal with very high scores, Richard Jenkins.

One day, the Captain summoned Alenko and Jenkins - the Normandy’s shakedown cruise had been rescheduled to start ASAP. Alenko wondered why Anderson wanted the tactical team aboard for a test flight, and soon realised that something was afoot - the brand-new Normandy was loaded for bear, the full crew was present and on high readiness (including the whole marine contingent) and three VIPs were aboard - Anderson, Shepard and a turian high-level agent of the Council.

As Alenko familiarised himself with the new ship and his new colleagues, he waited for the other shoe to drop.

Description

Staff Lieutenant Alenko is in his early 30s, though he looks a bit older. Like most people serving in the Alliance he has a mixed heritage — “Kaidan” might be Japanese or Arabic, “Alenko” is usually Ukrainian or Magyar, and his features seem part-European and part-Central Asian.

Kaidan sports a muscular, broad-shouldered physique - since most male Alliance Marines are built similarly, this is likely in vivo military gene therapy facilitating fitness and muscle development to operate in body armour. He has ruggedly handsome features and a distinctive, husky voice.

Alenko sports a peculiar haircut - more or less a pompadour, complete with sideburns. Perhaps he really likes 1950s rock ’n’ roll.

Alenko’s hard suits sports a distinctive model of faceplate when in sealed mode. Presumably this is because of his sensitivity to bright lights caused by his migraines.

Here is a video chaining various bits of dialogue with Kaidan to provide plenty of exemples about his voice and looks :

Personality

Alenko is reliable, smart, and professional - an excellent lieutenant. He tends to keep to himself, in large part because his migraines cut on his socialisation time. He’s a cautious, self-reliant, serious man and proud to be a marine.

His whole life has taken place in harsh, regimented environments such as Brain Camp and the Systems Alliance Marines. He’s well-adapted to those, and barracks life coupled with his natural curiosity have led him to read a lot - Kaidan knows about a surprising number of things, and his military assignments have generally been interesting and enriching since he’s considered a high-potential officer.

By contrast, Kaidan is somewhat sheltered - he never had much of a life outside of bases, and his migraines mean he didn’t generally join other marines partying on leaves. One of his troopers, Chief Williams, was very amused to see her Lt. ’s reaction when they visited a strip club with gorgeous asari dancers. This lack of a normal life also make Alenko a bit clumsy with women he’s interested in, though he’s smart enough, and enough of a straight shooter for it to be more cute than embarrassing.

His strange life can occasionally make his reactions a bit odd. He can shrug about his personal issues and just move on with equanimity, yet grow fascinated or even agitated about matters of galactic politics and leadership that most would consider distant, abstract concerns - and Kaidan cannot quite explain why he feels strongly about those. Like Shepard, he thinks that humanity’s destiny lies in joining the galactic community and fitting in well with aliens, though he’s much more reserved about the Council than she is.

Whether Kaidan is going to overthink something, or be sensible and pragmatic about it, can be difficult to predict - but he’ll usually over-intellectualise things. Kaidan is terrible at small talk, as he’s always focused on the facts, strategising, and analyzing the situation.

Kaidan developed an attraction toward the striking and charismatic Commander Shepard soon after joining the Normandy crew. Though he knew it was a terrible idea, he then misread some signals as the mistook Shepard’s warm and caring attitude for romantic interest on her part. As he tried to breach the situation while remaining professional, he realised that Shepard had something going on with the asari academic consultant on Normandy - and misread that by assuming that Commander Shepard preferred women. As they continued to work with each other Alenko reached a better understanding of the situation. Though he presumably felt like an idiot for a while, Kaidan is not a man to wallow in angst and he quickly got over it, remaining an excellent lieutenant, comrade-in-arms and pal for Shepard.

After one of their comrades, Gunnery Chief Ashley Williams, sacrificed herself during a high-stake storming action, Alenko and Shepard grew closer as marine buddies, mourning Williams together.

Crawling from the wreckage

Kaidan appears but briefly in the second game. He survives the destruction of the Normandy, but the loss of Shepard, Pressly and a score of crewmen considerably worsens the case of survivor’s guilt he’s been experiencing since Virmire.

With Shepard out of the picture, Alenko becomes an important Special Forces operative for the Systems Alliance, partially replacing Shepard after she was snatched by the Council then killed. Kaidan becomes a Staff Commander circa 2184, and is detailed to handling sensitive situations. His career during that time is undocumented.

Commander Alenko presumably also enjoys a certain popularity among the L2 biotic community, as he helped Commander Shepard negotiate a bloodless end to a biotic terrorist hostage crisis. These negotiations led to a revision of the Alliance’s reparation policies for L2 biotics, allowing sick biotics previously left to fend for themselves to receive medical and financial help.

In 2185 rumours that Shepard was still alive were floated toward Kaidan, as well as information about the human colony on Horizon (in the Terminus systems) being a likely target for a mass kidnapping raid. Assuming that Shepard would respond to such a raid, the Alliance sent Alenko to Horizon under the pretext of installing free automated defenses.

Even with the free anti-orbital batteries offered by the Alliance, the presence of an Earth agent was poorly received by the colonists - who offered but minimal collaboration as they had left Earth not to deal with its institutions. Presumably, Kaidan was on Horizon for but a few days when the kidnapping raid took place.

Kaidan survived the raid, apparently thanks to his biotic might, and confronted Shepard after she forced the kidnappers to depart prematurely.

Writeup completed on the 9th of March, 2012.