X5-494 is the Twin of Max's sibling Ben (X5-493).  We first met Alec,  when he was assigned to be Max (X5-452's) breeding partner back at Manticore.  Max named him Alec due to his smart-aleck attitude. 

While in Manticore, Alec helped Max escape in order to capture her and Eyes Only.

When Manticore was burnt down, Alec was living out in the world, free of Manticore, for the first time in his life.  One of the first things he did on the outside was get laid and develop an obsession with the 'boob tube' (TV).

He helped save Max from Ames White but in a later episode he tried to kill her and Joshua, after White implanted a bomb in his neck.  In the end he couldn't go through with it.  Max took him to a Manticore lab-tech and, reluctantly, paid for the bomb to be removed. 

After a while, Alec turned up at Jam-Pony looking for a job, mainly to get a sector pass and to scout out possible locations to rob.  Normal, employed him straight away 'cause of a case of hero-worship after seeing Alec in a cage-fight.  Since then Normal's developed a pretty unhealthy obsession with Alec (having frequent 'Gladiator' dreams about him).

Mid-Season, we found out a little about Alec's past.  We find out that in 2018/19, Alec was sent on a mission to spy on, and later assassinate Mr Robert Berrisford.  Alec posed as Berrisford's daughters' piano teacher Simon Lehane  (after learning to play at at concert pianist level within 24 hours).  Only problem was, Alec fell in love with Rachel (Berrisford's daughter).  After being ordered to kill Berrisford, Alec rigged their car with a bomb but, at the last minute, he told Rachel who he really was and warned her he was snet to kill her and her Father.  Rachel slapped him and ran out to save her father and got caught in the explosion.  Alec was dragged back to Manticore into Psy Ops and made to forget. 

Alec's relationship with Max is...well...he pretty much annoys the hell out of her on a regular basis.  She blames him for the virus and...well everything else going wrong in her life but behind that they've always got each others' back.  Alec helps Max save transgenics and look after Joshua.

In 'Hello, Goodbye' Alec was arrested for murder. Max helped him escape and told him that Ben was the killer (from Season One, 'Pollo Loco') Afterwards, Alec hides out at Max's and she tells him how Ben really died and a little bit about her childhood.

Logan catches Alec leaving Max's place the next morning and assumes they are together (which Max doesn't deny).  Alec's pretty annoyed about being the bad guy in Max's eyes yet again but goes along with her little ploy to stay away from Logan. 

We met Biggs, an old unit member of Alec's from Manticore but he was murdered by an angry street mob after being identified with thermal scanners.

During the Season Finale, Alec, Max and the others come up against The Phalanx - the elite warriors of Familiars. Logan saved Alec when he was getting his ass kicked (he had been shot in the shoulder).  Alec stood by Max's plan to stay and fight for the transgenics and currently resides in Terminal City.