In Left 4 Dead 2, he is the buddy of the survivor, Ellis. He grew up in Savanah with Ellis together, having all sorts of adventures, They were separated when the infection began, but Ellis still brags about his buddy Keith whenever he gets the chance.
Keith has supposedly survived these, as well as several other incidents, as explained by Ellis:
Burned on 90% of his body on multiple occasions.
Thrown through a car windshield breaking both of his legs.
Ran over by his own mower. 90% of his body cut up.
Teargassed.
Bombed with chemical, frag, and incinerary bombs.
Stabbed in the back by a ghost, or possibly a hobo.

There is some speculation whether Keith is a real person or not.
"This one time, me and my buddy Keith..."
"Ellis, not the best time."
by Kil Lerown January 07, 2010

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some who has a huge cock and hanegs out with one weird kid and one very tall kid and a funny kid and keith can demolish any type of pussy and if a girl ask who keith is she will say oooh mmmyyyy godd im hadicaped
hey when i grow up i wanna be keith
by gfbdsadfd June 16, 2011

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Keith is an amazing guy, who at first glance is shy and quiet, but once truly knowing him you'll be suprised how smart, strong, intelligent, funny, and thoughtful he is. Keith has a hard background and will tell you everything once you earn his trust and once you do try not to lose it. Keith doesn't brag or boast about what he has, rich kid or not, and will always help you out when you need it trying to make sure you're okay before he is.
Crystal: *sigh* Keith is so sweet and incredible and has such a nice build, I can't help but like him... I wonder if he'll like me back?
Friend: He will, trust me!
by #Keiana April 18, 2015

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A Keith,
A Guy that is so amazingly hott he doesn't know it. He really has no clue. Funny, considering he is so intelligent you think he'd get it.. Has a really handsome smile and these bright eyes that make you shiver and giggle. He's sweet natured and kind. Goofy and tends to do weird things like try to make you fart or bite your nails for you.. but probably the best guy you'll ever meet. Keith's are a catch and you usually don't know what to say to them except nervously texting "your awesome." Don't let him pay for you every time, it's amusing to see him get mad at the chinese lady for taking a girl's credit card over his. P.S. Amazing in Bed. Freaking Amazing. So pleasing it's unbearable.
Me: Keith! You are so sexy
Keith: No, I'm not.
Me: Seriously, Keith, Do I have to post pics to make you believe me?
by IiSaReDnEcKlOvEr September 06, 2013

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Keith. The Keith. Preferably Keith Koehler, male, was born at an unknown date, sometime in 19th century. Keith, THE Keith, also has a character of gold. Legend says he slain countless of mighty dragons, one from The Hobbit and Shrek. However, being the mysterious, Royal, but modest person that he is, he likes to "keep it easy" and watch "The Osbournes" on Sky TV.

Creatures THE Keith has slain, but not limited to, that has been recorded: The Dodo Bird, The 300 teethed Walrus, Leonidas, Justin Bieber, Sarah Palin, George Bush, (however only George's brain was damaged, but a might victory nonetheless), Megan Fox (bad acting), Shelob, Sauron, Fiona's dragon ,Smog ,Rumplestilskin ,Adolf Hitler (this is why his body was never found), The Infamous Abraham ,Snowball ,Tom Sawyer, The Energizer Bunny ,Bowzer ,Reznov ,The infamous good Samaritan , Saddam Hussein, The ol' Osama trash bin Laden, LadyGentleman Gaga ,The Papal Bull, The Mack-Attack Virus, HQL's foreskin, Dead Mau5 (Quite literally) ,Master Chief ,The Royal Six ,Barney the Dinosaur, Dora the sexplorer, The Smurfinator ,Astoundead, (Noob Tubed), The Heavy Metal fan club, Linkin Park (For their new album) ,Blink 182 (For never staying broken up) ,One of Avril Lavigne's ex boy friend (the wuss who ran away 'cause they broke up), Courtney Love, William Shakespeare, The Evil and illegal Mary Jane, Bruce Willis ,Spongebob Squarepants (for ripping his favorite trunks), Goku, and The Boy with a 1,000 band tee's.
Almost like a psuedo Chuck Norris, being called a "Keith" is like calling someone that is being super nice 'Jesus'.

Yup, it's that serious.

"You're such a Keith man!!!"

"Thanks bro, I'll suck your dick in a few minutes".
by bugehoner January 05, 2011

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A Small dick boy
Wow that's a keith
by Star boy December 28, 2014

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Someone with a very strange sense of humour, usually someone who never gets round to moving out from his mums, tends to attract strange minx like creatures who worship the ground he walks on
minx: do you have your own place?
boy: No, I still live at home.
minx oh, your a Keith
by dayhater November 28, 2011

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