Forget every other organ, there is only one you need to fight: a heart. These fighters have that, and, although they’re missing limbs, you’d be an idiot to challenge them to a brawl. Welcome to the world of the “adaptive athlete” – Adrenalists born different or maimed in the course of every day life. Many adaptive athletes are injured vets returned from Afghanistan or Iraq. Some are tough guys who found themselves in the wrong place at the wrong time. No matter how they got here, if they’re on this list, there’s an excellent chance they will destroy you in the ring.

Nick Newell (Height: 5’10 – Weight: 155 lbs)

Newell is a congenital amputee. He was born without his left hand and with only a few inches of forearm past the elbow. The “disability” is mostly harmless to him, but it regularly knocks the crap out of the MMA fighters who find themselves pitted against him in the octagon. Newell is undefeated (7-0), with only one of his fights reaching decision. Check him out on YouTube. Oh, you probably already have (he’s a sensation). The following entries here may be the next big thing in adaptive MMA.

Keith Miner (Height: 6’1 – Weight: 155 lbs)

In 2008. Keith Miner became the first amputee to fight MMA professionally. Just 8 years earlier, he lost his right hand after he was pulled into an industrial wood chipper. Now he grinds up able bodied athletes like they are twigs. Check the stats: he’s 5-3, with his latest victory awarded in just one minute via TKO. Unlike Nick Newell, Miner uses his unconventional limb as a striking weapon. Prior to fights, he must have his specially-tailored “glove” approved by the referee.

Matt Betzold (Height: N/A – Weight: 145 lbs)

When he was just six years old, Matt Betzold ate something that he never could have known was dangerous: a piece of candy, filled with poisonous mushroom spores, and intended as a weapon of revenge against his own father. The candy put Betzold in a coma for six weeks. When he awoke, he awoke without his left leg. Now 28, Betzold has trained himself to overcome, first a disability, now able-bodied opponents. Betzold is 3-3 during his professional MMA career, most recently submitting Rudy Kennedy on May 12, 2012 with a rear-naked choke. Betzold excels at the floor game – it is the milieu he calls home, shuffling across the mat like a weaponized inch-worm. If you know what’s good for you, you won’t call him that.

Kyle Maynard (Height: N/A – Weight: 135 lbs)

Maybe you’ve heard of Kyle Maynard. A quadruple congenital amputee, Maynard has appeared on Oprah, modeled for Abercrombie & Fitch, and in 2004 he won the ESPN Espy Award for Best Athlete with a Disability. Just this past January, Maynard became the first quadruple amputee to climb all 19,340 feet of Mount Kilimanjaro completely on his own. He did so with bike tires wrapped around his limbs to protect himself from Kilimanjaro’s notoriously sharp lava rock. Perhaps Maynard’s most impressive feat, however, is his fight record. In high school, he amassed a 35-16 wrestling record. That is 35 wins against wrestlers armed with a pair of arms and legs – a sizable advantage. In 2009, Maynard took his skills and unstoppable drive into the MMA cage at Auburn Covered Arena in Alabama where he fought Bryan Fry. Maynard had one advantage: Fry would not be able to kick or knee Maynard in the head; when fighting, Maynard is always considered a “grounded” opponent. That was Maynard’s only advantage, and it wasn’t enough to bring him a victory in the only MMA fight he ever participated in. It was, however, enough to impress the hell out of us.

Jason “Blind Fury” Keaton (Height: 5’11 – Weight: 190 lbs)

They don’t call him “Blind Fury” for nothing. Keaton is legally blind, and his fighting style is furious. In amateur and officially sanctioned MMA events, Keaton has amassed a record of 4-1, taking out 3 of his opponents with what appears to be his favorite finishing move: the armbar. Perhaps it’s no surprise Keaton chooses close combat; he can’t make out his opponents unless they are close enough to strike. When he does, he does so furiously, employing a style of Brazilian Jui Jitsu that he can call all his own. It’s a style you’d be smart to stay far, far away from.