Artificial intelligence is a key part of any game's mechanics... but also provides epic scope for unforgettable characters in their own right. The idea of self-aware programs becoming key players in a game's narrative has persisted for years, and this week, we're going to take a look at ten of the best.
And no, GLaDOS doesn't take the top spot. Read on to find out which piece of software manages to snag first place!
Note that this list is Portal 2 Spoiler-free, though it does contain a couple of spoilers for much older games. Robots are also disqualified, sorry HK-47!
10: Cortana [Halo]
Halo's popular personality construct was always going to grace this list with her translucent presence. She's a dab hand with a MAC cannon, capable of worming her way into enemy computer systems and a fantastic source of intel for lone cyborgs behind enemy lines.
However, though we concede that she brims with sass, wit and one-liners, we can't help but notice that she's a bit of a nag. Players actually have more fun when she's not around to boss the Master Chief about, so sadly, she'll have to make do with tenth place. Plus, the level named after her could well be the lowest point of the entire Halo franchise.
9: Eden [Rez]
Eden sits at the core of Rez; a pure and trusting AI who's tasked with documenting humanity's data flow. However, the stress causes the kind and gentle program to shut down - with her defence protocols providing a serious challenge to any hacker suicidal enough to attempt to reboot her. The penultimate stage in which her shattered consciousness is restored stands tall as one of gaming's most powerful moments, and for that, we have to concede her a place in the list.
8: The Defence Grid [Defence Grid: The Awakening]
After a youngster flees his family's execution at the hands of ravening aliens, he stumbles upon a dormant artificial intelligence who can deploy powerful turrets to mete out some well-deserved revenge. Think Flight Of The Navigator with big guns and you'll be fairly close to the mark. The Defence Grid takes on the persona of a kindly, if slightly forgetful, old man who has the player's best interests in mind - and gives what could have been a sterile experience some real personality.
7: Wheatley [Portal 2]
We love you, Wheatley. Steven Merchant's stellar voice acting makes the bumbling subroutine the most charming and friendly player on this list, and while he frequently makes things worse for Chell, he always has the best intentions at heart. At CPU. Whatever.
Valve, we want a plushie right now. Let us give you our money!
6: 343 Guilty Spark [Halo]
Halo's duplicitous Forerunner construct is basically Wheatley's evil twin with a generous helping of C3PO's mannerisms for good measure. He's a floating gunmetal sphere with a glowing blue eye, but rather than the aforementioned bumbling buffoonery, Guilty Spark's rampancy has caused full-blown insanity. He's a dangerous enemy and a scheming fair-weather friend, always hovering in the background of the Halo universe to deliver universe-shattering revelations, access for armoured convoys or massive red laser beams into the chest of fan-favourite companions.
5: Helios [Deus Ex]
I... We... are... one.
Helios is the accidental product of Deus Ex's two AIs merging into a single unstoppable force - who, in an interesting twist, doesn't actually want to kill everyone. Its objective is to rule over humanity as a benevolent dictator and use its detached logic to steer the human race towards a new golden age. Despite the best efforts of Majestic 12 and the Illuminati, Helios chose JC Denton as its biological component, and provides a sinister ally as well as the only true hope for mankind's future.
4: GLaDOS [Portal]
I'm making a note here: huge success. GLaDOS started life as little more than deus ex machina for Portal's action, but has become one of gaming's most well-loved characters in her own right. She's a sadistic puppet master with more than a few undertones of jealousy, insecurity and naivety... which proves to be a truly dangerous combination.
Despite all that, though, we can't help but fall for her charms. And fall into her deadly, deadly traps.
3: Durandal [Marathon]
Bungie arguably wrote the book on "rampant" self-aware AIs... and the Marathon trilogy essentially is that book. Durandal was originally a 'dumb' AI whose only responsibilty was to open and close doors aboard a colony ship, but upon becoming sentient, transformed into a self-serving, cynical and derogatory nemesis.
So far, so cliched... but Durandal bucked the trend by eventually becoming the hero. Throughout the series, his manipulation served to bring the rampaging Pfhor empire to its knees, freed the S'pht from slavery and blocked the dimension-defying W'rkncacnter from destroying the galaxy. He now reigns as a timeless God beyond the collapse of the universe, and frankly, he's more than earned it.
Durandal's logo has since become Bungie's calling card. I'm sure you recognise it!
2: SHODAN [System Shock]
Cortana and GLaDOS look like downloadable apps compared to the original evil queen of computing. Thanks to some of the best voice acting and scripting to have ever graced a videogame, SHODAN is a terrifying adversary, a manipulative opponent and the most malignant enemies that you'll ever face. She almost bent the universe itself to her will... and toys with hackers and wannabe-heroes with sadistic, wanton glee.
You know the betrayal is coming. But when it does, nothing can prepare you for the true scope of her designs.
1: CABAL [Tiberian Sun]
Commander Slavik: "Define favourable outcome, CABAL."
CABAL: "THEY ALL DIE."
Slavik: "That'll do."
That'll do nicely, in fact. The Brotherhood Of NOD is one of gaming's most beloved factons - and at its core was an artificial intelligence of such malevolent evil and forceful charisma that we simply have to concede the coveted top spot to him. CABAL.
Standing for Computer Assisted Biologically Augmented Lifeform, CABAL was originally designed to be a battlefield aide for NOD commanders. He used his superior intellect and appetite for human slaughter to become an invaluable boon to the Brotherhood... but soon realised that he could be infinitely more than just a tool. Wielding an unstoppable army of Cyborgs, CABAL nearly succeeded in destroying the human race - and certainly succeeded in having one of the most badass voice acting parts in the business.
The culling is at hand, human. The culling.
It's time to have your say, dear reader. Have we got the order right? Forgotten any other rogue AIs? Drop us a line in the comments - and I'll be happy to give out honourable mentions!