“We finally get out here and the 'final frontier' was already settled. And the residents don't even seem impressed by the view. Or the dangers.”

Kaidan Alenko is a human Sentinel and a Systems Alliance Marine. While serving aboard the SSV Normandy, he was a Staff Lieutenant and head of the ship's Marine detail. He also was an initial member of Commander Shepard's squad. Kaidan is a biotic wired with the controversial L2 implants, which are known to cause severe neurological damage to the user. However, he is fortunate enough to only suffer from occasional severe migraines. He is a possible love interest.

Kaidan Alenko is voiced by Raphael Sbarge.

Mass Effect


ME1 Sentinel Ally


Kaidan was born in 2151 into a family already familiar with space: his father served in the Alliance military. After his mother was downwind of a transport crash in Singapore, Kaidan was exposed in utero to element zero and beat the odds, gaining biotic potential instead of terminal brain cancer. At the time little was known about human biotics, but when the possibilities became better understood, a company called Conatix Industries was set up to track accidental eezo exposures. Children who showed enough potential to be worth augmenting with implants were 'encouraged' to attend BAaT (Biotic Acclimation and Temperance Training) which was conducted at Gagarin Station and nicknamed 'Brain Camp' by its attendees. As Kaidan tells Shepard, "a bunch of guys in suits show up at your door after school, and next thing you know, you're out on Jump Zero."

Chakwas and Kaidan Post Eden Prime

Along with several other teenagers, including a beautiful, gentle girl named Rahna, Kaidan began his training but things went bad almost from the start. Conatix wanted to speed the work along and brought in an ex-military turian, Commander Vyrnnus, who was an expert in biotics but also a veteran of the First Contact War who disliked humans. Vyrnnus introduced himself by saying "I was at the helm of the dreadnought that killed your father", and Kaidan retorted that his father hadn't even been in the war. Vyrnnus had it in for Kaidan after that, and began pushing the teenagers very hard. Kaidan recalls: "You either came out a superman or a wreck. A lot of kids snapped. A few died."

Finally, the inevitable happened and Vyrnnus went too far. Rahna, who had become close to Kaidan during their training, reached for a glass of water instead of moving it biotically. Vyrnnus punished Rahna by breaking her arm and Kaidan tried to defend her, only to receive a beating from Vyrnnus. When the turian pulled a knife, Kaidan lost control and hit him with a full biotic kick, breaking Vyrnnus' neck. After Vyrnnus' death, BAaT was shut down and the records were sealed to hide the Alliance's mistakes. Though Rahna was safe from Vyrnnus, she was afraid of Kaidan after that and the two parted ways.

Kaidan dropped off the radar for a while to figure things out, feeling lost and paralyzed after Jump Zero, but eventually came back to the Alliance in 2173 — on his terms this time — because he wanted to serve. Refusing further biotic training or an implant retrofit, he enlisted in the Alliance Navy and worked his way up to Lieutenant, gaining several special commendations in the process despite the health problems he suffered with his L2 implants; these manifested as intense migraines that left him sensitive to bright lights and noise. Finally Kaidan was transferred to the SSV Normandy under Captain Anderson, where he later worked alongside Commander Shepard.

His experiences at BAaT and his long service make Kaidan politically savvy, but very conservative, cautious and self controlled. Originally, Kaidan was hesitant to use his abilities on living targets, but he changes his mind after seeing the destruction on Eden Prime. During the mission on Eden Prime, Kaidan was deeply affected by seeing his comrade and friend Richard L. Jenkins gunned down, his first friend lost in combat. Though he is a biotic, Kaidan's loyalty is to the Alliance and he has no sympathies for biotic extremists. He doesn't bear any ill-will toward alien races, even turians: Vyrnnus made him see aliens as individuals and actually taught him how 'human' aliens are, "they're jerks and saints, just like us." Kaidan believes humans, as newcomers to the galactic community, shouldn't have a Council seat until they're ready for one, and Ambassador Udina is doing more harm than good by pushing too hard. Shepard can discuss this with him and (if female) can even Charm or Intimidate Kaidan into becoming much more xenophobic and pro-humanity.


If asked, Kaidan can give feedback on recent missions, discuss the commander's decisions and give some insight into the crew's state of mind. Knowing they're going to be faced with difficult choices without reinforcements, Kaidan urges Shepard not to cut corners as Vyrnnus did, and always leave a way out to ensure nobody gets hurt further down the line. However, as the mission progresses Kaidan becomes concerned about the lack of backup from the Citadel Council. The evidence Shepard is gathering about Saren Arterius and the threat of the Reapers seems too much to ignore, but the Council just doesn't want to believe anything's wrong — proving 'human nature' carries across species.

During the operation at Virmire, Shepard can choose to save Kaidan's life at the cost of losing Ashley. Kaidan is an experienced marine who knows that Ash volunteered for the mission, but he's never lost a soldier under his command to hostile action. Kaidan becomes determined to make the Council listen to their evidence about the Reapers: if all the Citadel races rally to stop the machines, it will be a fitting tribute to Ashley.

If Kaidan goes with Shepard to Ilos, he is moved by the fate of the Protheans, knowing their sacrifice has given them all a fighting chance. Unless Shepard has persuaded him to adopt a more xenophobic view, during the assault on the Citadel he tells Shepard to save the Council, even though he knows it will cost many human lives.


“That's what I lo— appreciate about you.”

If Shepard is female, Kaidan is attracted to her from the beginning. He tries to save her from the Prothean Beacon on Eden Prime and, thinking he triggered it when he got too close, blames himself for her suffering. He also slips up when he, Ashley and Shepard are taking in the view on the Citadel by inadvertently admitting he finds the Commander beautiful, much to Ashley's amusement.

When the Normandy is locked down by the Council, Kaidan offers Shepard his comfort and support, and they almost share a kiss before being interrupted by Joker. Once they are finally en route to Ilos, Kaidan goes to Shepard to talk about the mutiny and the upcoming battle, wanting her to know that he's enjoyed serving alongside her. After some prompting by Shepard, he finally lets go; from what he can see, everything else in the galaxy, even the Reapers, will come around again, but the two of them are what is important right now — "this is what will never happen again. Us." Kaidan claims Shepard makes him feel human, and they can spend the night together, as long as nothing changes, and their duty to the Normandy's crew still comes first.

Mass Effect 2

If Kaidan survived Virmire, he continued to serve under Shepard aboard the Normandy. During a routine patrol hunting for geth forces, the ship came under attack from a warship belonging to the enigmatic Collectors and Shepard forced Alenko to evacuate with the rest of the crew. Soon after Kaidan got the survivors out in an escape pod, the Collector ship fired again, destroying the Normandy and causing Shepard's death. Suffering from survivor's guilt at the loss of his ship and his commanding officer, Kaidan remained in the Systems Alliance, eventually coming to terms with his pain. Over time he was promoted to Staff Commander.

In 2185, Alliance colonies began vanishing en masse, and Alliance Command began to wonder if Cerberus was responsible. Kaidan also began hearing rumours that Shepard was alive and somehow involved with Cerberus, then received a tipoff that the human colony of Horizon might be the next target. Kaidan was dispatched to investigate, and began installing defense towers as a cover for his investigation into Cerberus. However he ran into hostility from the colonists, who didn't like Alliance involvement in their affairs. They believed the defence towers actually made them more of a target, and resented Kaidan's presence.

The tip paid off when Horizon was attacked by the Collectors, though they arrived before the defence towers were ready. Kaidan tried to defend the colonists but was stung by a seeker swarm and paralysed. Somehow he managed to shake off the effects and avoid capture by the Collectors, in time to be reunited with Shepard, who had raced to Horizon to save the colony and activated the defence towers to drive off the Collector ship.

Though initially pleased to see the Commander, Kaidan soon became wary of Shepard's involvement with Cerberus. He refused to entertain any thoughts of joining the mission, claiming he was an Alliance soldier and always would be, and that he could never trust Cerberus. He left to report to the Citadel, but warned Shepard to be careful.

If Kaidan died on Virmire, while searching the wreck of the first Normandy, Shepard will briefly see Kaidan's face in a flashback. The Galactic News may also mention that an Alenko Memorial Fund has been set up and sending biotic children to the Ascension Project.


If Kaidan and Shepard had a romance in Mass Effect, Kaidan takes her in his arms upon being reunited on Horizon, but his relief at seeing her alive soon turns to anger. He demands to know why Shepard didn't try to contact him and forced him to go through the pain of thinking she was dead for two years. He claims that working with Cerberus is a betrayal of everything they stood for, and leaves to report.

After leaving Horizon, Shepard receives an email titled "About Horizon..." from Kaidan:


I'm sorry for what I said back on Horizon. I spent two years pulling myself back together after you went down with the Normandy. It took me a long time to get over my guilt for surviving and move on. I'd finally let my friends talk me into going out for drinks with a doctor on the Citadel. Nothing serious, but trying to let myself have a life again, you know?

Then I saw you, and everything pulled hard to port. You were standing in front of me, but you were with Cerberus. I guess I really don't know who either of us is anymore. Do you even remember that night before Ilos? That night meant everything to me... maybe it meant as much to you. But a lot has changed in the last two years and I can't just put that aside.

But please be careful. I've watched too many people close to me die -- on Eden Prime, on Virmire, on Horizon, on the Normandy. I couldn't bear it if I lost you again. If you're still the woman I remember I know you'll find a way to stop these Collector attacks. But Cerberus is too dangerous to be trusted. Watch yourself.

When things settle down a little... maybe... I don't know. Just take care.


For her part, Shepard will keep a picture of Kaidan in her quarters, on her desk between her personal terminal and the Medal of Honor. Should Shepard choose to maintain the relationship with Kaidan, before going through the Omega 4 Relay, she will gaze at the picture before leaving. If Shepard becomes involved in a relationship with another crew member, she will eventually turn the picture face-down on her desk.

Mass Effect 3

Weapon proficiencies



Kaidan ME3 Character Shot

Kaidan will return as a squad member in Mass Effect 3, provided he survived the events on Virmire in Mass Effect. If he did not, Ashley Williams will take his place in the squad. By the time of the events of Mass Effect 3, Kaidan has been promoted to Major and commands the 1st Special Operations Biotic Company, a covert operations unit.

During the Reapers' invasion of Earth, Kaidan assists in evacuating Shepard from Earth on-board the Normandy SR-2. Kaidan then joins Shepard to a mission to recover Prothean data on Mars, where he displays great tactical and combat aptitude. However, he still does not fully trust the Commander, as he believes that Shepard may be a puppet for the Illusive Man. At the end of the mission, he confronts the Cerberus android responsible for the base's destruction, but he is severely injured by it. He is taken to Huerta Memorial Hospital on the Citadel, where he slowly recuperates. While recovering, Udina offers a Spectre status to him which he accepts.

Shepard will be able to speak to Kaidan by visiting him in the hospital after every priority mission. If Shepard romanced Kaidan, then there is the option to continue the romance. In time, Kaidan recovers from his injuries and accepts Udina's offer. When Cerberus invades the Citadel, Kaidan is tasked to protect the Councilors but is unaware that Udina and Cerberus are actually collaborating to take control of the Council. This puts Shepard and Kaidan in a conflict; Shepard must then convince Kaidan of the truth behind the attack.

Depending on past interactions with him, Kaidan can be talked down. If Shepard cannot persuade Kaidan to back off, Shepard will kill Kaidan. If Kaidan lives past this event, he can either be recruited back into Shepard's squad on board the Normandy or left behind to provide assistance in the war.

If Kaidan is left behind on Virmire, or killed during the Cerberus coup attempt, his name will appear on the Memorial wall aboard the Normandy.

If Kaidan is in the squad at the final push towards the Conduit, he will be killed by Harbinger if the Effective Military Strength is too low.


“I want to understand what this is between us...and make it real.”

A female Shepard who romanced Kaidan in the first Mass Effect has differing dialogue with him during the Priority: Mars mission, where they discuss their relationship, and Kaidan's fears that she is no longer the woman he loved. She can either be consoling or confrontational.

While in the hospital, Kaidan will send a message to Shepard asking to meet with her. If Shepard romanced another character during Mass Effect 2, Kaidan will ask her about it, where she can either apologize, explain herself, or lie. Lying will make Kaidan angry and he will order her out of the room, although she has the chance to admit her lie and apologize. If she apologizes or attempts to explain, Kaidan remarks that he still cares about her, and there is no other woman in his life. Kaidan makes no distinction between any of the crew that Shepard romanced.

If Kaidan joins the crew after Priority: Citadel II, Shepard can resume a romance with him, or start a new one if she did not do so before. He invites her out for a drink at Apollo's Cafe, where he reminisces that he often had a few beers at his parents's home overlooking English Bay in Vancouver. He'll reflect on their relationship, and wonders if they have a future together. He'll also forgive her for cheating on him. Shepard can lock in a relationship here by telling him that she loves him.

If Kaidan was not romanced in Mass Effect, either a male[1][2] or female Shepard can romance him in Mass Effect 3. They can do so by visiting him in the hospital, picking him up a bottle of whiskey from the Sirta Supplies store, and locking in the romance when Kaidan talks about how he never looked for a relationship before while at Apollo's Cafe.

In the very last moments of the game, if Kaidan was romanced, the last person Shepard will see is Kaidan smiling.


  • If Shepard has any biotic talents, Kaidan will claim that though his abilities spike higher than most L3s, Shepard is the exception, indicating that the Commander is an L3. This appears to occur regardless of Shepard's class.
  • On the PS3 version of Mass Effect 2, if Kaidan died on Virmire, his picture may appear in Shepard's cabin even if he was not the chosen love interest in Mass Effect: Genesis, possibly caused by a glitch in the game.[3]
  • His name is sometimes spelled "Kaiden" in external media (such as the Character Spotlight), but is always spelled "Kaidan" in-game.
  • Raphael Sbarge also voiced Republic officer Carth Onasi in BioWare's Star Wars: Knights of the Old Republic.
  • Hidden dialogue shows Kaidan at some point was intended to be a romance option for a male Shepard in Mass Effect, but this option was removed in the final version. It is possible for a male Shepard to have a romance with Kaidan through the use of save edits, although some of the dialogue options are missing.
  • When Kaidan is encountered in the opening for Mass Effect 2 and later on Horizon, he is wearing Medium Armour, though in Mass Effect, he could only equip Light Armour.
  • On November 24, 2011, Raphael Sbarge, as a Thanksgiving Day present, released a sound file where he voices Kaidan's apology email to Shepard in Mass Effect 2 after the two meet on Horizon. The sound file was later taken down but was rereleased on YouTube
  • As with all squad members, Kaidan has unique dialogue that can be heard at various locations, during missions or assignments, or if a specific squad member is in the selected team.


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