Our shields can't repel Badassery of that magnitude...!

Throughout the history of fiction, there have been a number of characters. No, wait. That's a complete understatement. There have been a crapload of characters. However, once in a while, you'll be reading a book, watching a show, or playing a game, and some one takes five thousand arrows to their chest as well as a cannonball but just walks it off with a smile. That, my friends, is the badass. He represents everything that is awesome either by doing awesome things, saying awesome things, or just being the personification of awesome.

Okay, let’s break down the facts, here. Cars: Awesome. Robots: Awesome. Cars that turn into robots: Sign me up. This is the mentality Hasbro had when they decided to start their Transformers line back in 1984. However, they knew not what they were about to unleash upon the world.

So the Transformers have two warring factions- the Autobots (Good guys) and the Decepticons (Bad guys). In the original cartoon, the Decepticons had Megatron at their helm, a robot that turned into a gun- which is pretty insane to begin with. However, he also wields a Fusion Cannon, a weapon that shoots pretty purple lasers, which everyone fears. Everyone, except Optimus Prime.

The Original Optimus Prime was a badass because he kicked ass, took names, and when one of the smaller bots proved their worth on the battlefield, he would give them a damn hug. Not only cold and unrelenting on the battlefield, he was also affectionate and effective in commanding his forces back at the base, and also at dealing with humans. He was the embodiment of an excellent leader, and role model. However, he also laid the smackdown on the Decepticons every day, and often in amazingly epic ways. He even played basketball.

Optimus Prime has appeared as some form of truck in every Transformers Series he is featured in, which is essentially all of them. He often has super modes that further enhance his badassery- rocket pants, shoulder bazookas, and even Voltron-esque limbs. He continues to effectively lead the Autobots in their battle to destroy the evil forces of the Decepticons. Here are a few of the reasons he is a badass.

After 25 years, Prime is still in his... well, you know...

1) His voice is that of Peter Cullen, and it is made of awesome and win. Have you heard how that voice resonates? The amazing thing is that, in the 25 years since his creation, Peter Cullen has altered the voice to make him sound older and more wizened. His inspiration for the voice? A perfect leader, someone who would be able to show great command, compassion, and determination. He came up with the voice we know today.
2) In several fictions, Prime wields Energon weapons, often swords or axes. The axe is surprisingly his most well-known melee weapon, along with his ion cannon as a ranged weapon. Watching him whip out the first orange Energon Sword in the first live-action movie signifies hardcore ownage will commence.
3) He is capable of saying badass one-liners, such as “Freedom is the right of all sentient beings,” “Fate rarely calls upon us at a moment of our choosing,” and “Autobots, Transform and Roll Out!” Not always wise and in control, Prime has shown a wide range of emotions, and there's even a website, thequotableoptimusprime.com, dedicated to chronicling his epic lines. 
4) He takes faces. See, the first live action movie and Revenge of the Fallen.

5) He is the bearer of a legendary artifact called the Autobot Matrix of Leadership. It’s basically the “I’m leader, screw everyone else” token. The Matrix is a device that contains all of the wisdom of those who once bore the Prime mantle, and also signifies the one who can open it is a rightful leader.
6) A slick paint job. Blue and red never looked so good. It always comes back to this iconic color scheme, and, flames or not, we always know that it's Optimus Prime because of it.
7) He has died and returned to life more times than Jesus. Just because he’s that good.

Optimus Prime represents everything that is right in the world- guns, swords, robots, cars, heroes, and change. The past three iterations of Prime have done ridiculous and badass things: wielded a freaking Thunder Hammer and worn a jetpack, dual wielded swords and ripped heads in two, and in War for Cybertron, he's been jacked up on Energon so that he looks like something from Gears of War. As long as Optimus Prime still represents his original image, he will continue to be a badass. There's one thing that every iteration of Prime must be able to do, and that is be absolutely awesome.

Rather than attempt to explain this to you, I give you this:
http://www.youtube.com/watch?v=bBUAG6Gy-to
Megatron vs Optimus Prime. I mean, did you see that move he does at the beginning? He vaults over a bunch of Decepticons and picks them off in midair. He then dies trying to defeat Megatron. Stupid Hot Rod.

Not good enough for you? Here’s one of the coolest fights ever. I literally weep tears of joy whenever I watch this scene.
http://www.youtube.com/watch?v=XctuVzwERe4
That’s all I have to offer.