7. Nefarious from Ratchet & Clank

We love Clank as the loveable sidekick to Ratchet, but Dr. Nefarious is just the villain that this sci-fi series needed. Nefarious hates everything about organic life, even though he used to be organic himself. To satisfy his hatred, he spends most of the time concocting overly complicated plans to bring an end to life across the universe. Whether trying to transform every organism on every world into a robot, or changing time so the villains always win, Nefarious’ plots are too ridiculous to take seriously, and just the right challenge for the dynamic duo of Ratchet & Clank. A great villain can make a story, and Nefarious hits all the right notes to fit the franchise.

6. John Henry Eden (The President) from Fallout 3

Wandering the wasteland of a devastated Washington D.C., it’s hard to ignore the repeated radio broadcasts from John Henry Eden, the president of the Enclave that would bring the whole area under its control. Little do players realize that the charismatic voice over the airwaves is that of a computer. The President AI was created prior to the great war that devastated humanity as an amalgam of the personalities of past U.S. presidents. The program eventually gained self-awareness, and took over leadership of the militant organization. In a climactic confrontation, players eventually are forced to either side with the President and poison the nearby water supply, or outsmart the program through conversation until it self-destructs. As one of the great twists in Fallout 3’s story, John Henry Eden fits perfectly into the game’s themes of an America gone horribly wrong.

5. Dog from Half-Life 2

Not every great AI character needs to chat with the player. Alyx’s Dog of Half-Life 2 plays a part in some of the most thrilling scenes of the landmark game. It’s hard not to instantly like the hulking robotic powerhouse, after you’re introduced to him in an exaggerated game of “Fetch” involving a gravity gun and a rusty scrapyard of metal. From there, Dog’s loyalty to Alyx and ability to help Gordon Freeman out of his toughest scrapes wins him points again and again.  Excitable, eager to please, and fun to watch, it’s hard not to love the robotic companion, just like a real canine.