The sport of MMA suffered a loss tonight when it was revealed that former UFC heavyweight champion Kevin Randleman had passed away at age 44 due to heart failure.

Randleman (17-16) had a long career prior to his final fight in 2011. He captured UFC gold in 1999 and went on to take part in memorable fights under the defunct PRIDE banner and various other organizations.

“The Monster” was a pioneer of the sport, and the response to his unfortunate death proved as much. Check below for reactions from the MMA community following the news.

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Sad to confirm the passing of MMA pioneer Kevin Randleman at 44 years old. Went to hospital with pneumonia and had heart failure. — Jeremy Botter (@jeremybotter) February 12, 2016

With saddened hearts, the Randleman family confirms the passing of Kevin “The Monster” Randleman. Behind the name, was… Posted by KEVIN THE MONSTER RANDLEMAN on Friday, February 12, 2016

I’m so sorry to hear about the passing of the legend Kevin Randleman. RIP Kevin “The Monster" Randleman pic.twitter.com/MTC4nFAF29 — Dana White (@danawhite) February 12, 2016

We heard its confirmed, Kevin Randleman passed away. This is the worst news. Condolences to Elizabeth and their kids, RIP my friend — Bas Rutten (@BasRuttenMMA) February 12, 2016

The wrestling world lost a good one today!

Rest easy Monster! #BuckeyeNation pic.twitter.com/GhQgRGcNmi — Nicholas Sanchez (@Nsanchez141) February 12, 2016

UFC Legend, Kevin Randleman Passes Away At Age 44. Can't believe my friend passed away. That's 2 in 2 months WoW pic.twitter.com/1lmKyWcMEi — Gary H Goodridge (@garyhgoodridge) February 12, 2016

I'm stunned & deeply saddened at the passing of Kevin Randleman. He was responsible for the most memorable call of my 30 year career.#RIP — Mauro Ranallo (@mauroranallo) February 12, 2016

My condolences go out to Kevin Randleman's family & friends. Thank you for all the memories my friend! #PRIDEAndTheMonsterNeverDie — Mauro Ranallo (@mauroranallo) February 12, 2016

I always believed he had the potential to be one of the best ever but injuries & other issues derailed his career. #RIPMonster — Mauro Ranallo (@mauroranallo) February 12, 2016

Will never forget this finish, stunning at the time. RIP Kevin Randleman https://t.co/E3Wy0BY5IB — John Pollock (@iamjohnpollock) February 12, 2016

KEVIN Randleman- Such a great competitive spirt inside if an amazing athlete. He truly could do what ever he Believed he could do. #rip — FRANK TRIGG (@FRANKTRIGG) February 12, 2016

Very sad to hear about Kevin Randleman. I went to the UFC 95 fighter's hotel and he was the first person I saw. He was pretty nice. — Matheus Aquino (@MatheusDCAquino) February 12, 2016

We have lost one of my fav old school fighters from Ufc and pride days ! At age 44 Kevin was too young . Myself… https://t.co/7UELDuRvAU — Richy Walsh MMA (@RichyMMA) February 12, 2016

The world lost a beautiful man today💔who wore his whole heart on his sleeve with contagious energy RIP "The Monster" https://t.co/OXvdHy6QW3 — Gina Carano (@ginacarano) February 12, 2016

Kevin Randleman picked me up & put me on his shoulder after my first fight. Made me feel like a hero. RIP to a Monster w/ a heart of gold. — Julie Kedzie (@julesk_fighter) February 12, 2016

Devastating news to hear about the passing of Kevin Randleman. My heart is filled with sadness. Kevin was a longtime friend and a great guy. — Shannon Knapp (@shanknapp) February 12, 2016

Very sad to hear the passing of Kevin Randleman. One of the baddest dudes in his time. I became a fan after… https://t.co/8sYQiRhVUh — James Te Huna (@JamesTeHuna) February 12, 2016

RIP Monster. Thanks for making memories on the road that will live on forever… gutted. — Ken Pavia (@KenPavia) February 12, 2016

It was an honor to corner you in your last fight and I will tell the stories of the Russian hospital forever. #KevinRandleman #homie — Ken Pavia (@KenPavia) February 12, 2016

Sad news about my fellow veteran fighter….we saw this thing through when it wasn't the popular thing to do. May you RIP Randleman — Jens Pulver (@jens_pulver) February 12, 2016

My old friend & UFC Legend Kevin Randalman passed away today! RIP Big Brother! Thanks 4 the wisdom! #TheMonster pic.twitter.com/qdYS3AM51Q — Tim Credeur (@CrazyTimCredeur) February 12, 2016

Kevin Randleman was a legend but more importantly he was a friend. The world is a lesser place without him in it. #RIP — Damon Martin (@DamonMartin) February 12, 2016

Very sad to hear this news. https://t.co/H4O5shpGqJ — Kenny Florian (@kennyflorian) February 12, 2016

RIP @themonstah_ Kevin Randleman. Glad I got to meet him. A great guy that was all about his family. Condolences — Cesar Gracie (@CesarGracieBJJ) February 12, 2016

@themonstah_ RIP to an old friend! Great personality and true class! One of funniest characters I've met! Sad to hear this news. — Jeremy Stephens (@LiLHeathenMMA) February 12, 2016

I was on the line with Mark Hunt when the news broke of Kevin Randleman's passing. Here was his reaction. pic.twitter.com/xjEAzCK5PU — Justin Faux (@justinfauxmma) February 12, 2016

Just heard that the MMA community lost a great fighter tonight at only 44 yrs old. RIP Kevin Randleman. Prayers go out to his family. — Rich Franklin (@RichFranklin) February 12, 2016

My first MMA interview was with Kevin Randleman in 2000. I knew I was sticking around after that. #RIP to a true original. He will be missed — Thomas Gerbasi (@tgerbasi) February 12, 2016

Rest in Peace Randleman #rip — Antonio Pezao Silva (@BigfootSilva) February 12, 2016

Just hearing about #KevinRandelman 's passing. I remember the first time I watched him wrestle in the finals of the NCAA's. I was in awe. — Aaron Simpson (@aaronsimpson) February 12, 2016

Shocked at the passing of Kevin "The Monster" Randleman at just 44 years old. RIP to a true pioneer of mma. #legend pic.twitter.com/pIRx7QIaqo — John Maguire (@MaguireTheOne) February 12, 2016

Just read about Kevin. He was a someone I looked up to long before I ever thought about being a part of this sport — Scott jorgensen (@Scottjorgensen) February 12, 2016

I got to know Kevin and train alongside and with him and he was a giant but was always a great guy to train with. He had a powerful attitude — Scott jorgensen (@Scottjorgensen) February 12, 2016

That always positively no acted me when I was around him. #RIP — Scott jorgensen (@Scottjorgensen) February 12, 2016

RIP Kevin Randleman. Pioneer of the sport. — Scott Holtzman (@HotSauceHoltzy) February 12, 2016

Was on the phone facilitating interviews w/ Melvin Guillard when he heard about Kevin Randleman's passing. Fighting back tears… (1/2) — C.J. Tuʇʇle (@kidceej) February 12, 2016

Guillard told me he idolized Randleman. So much so that he asked "The Monster's" permission to bleach his hair early in his career. #RIP 2/2 — C.J. Tuʇʇle (@kidceej) February 12, 2016

MMA fighters are dying way too young. Take care of yourselves out there guys. #RIPRandleman — kajan johnson (@IamRagin) February 12, 2016

Can't believe this, We just lost one of the greats. I'm glad I was able to know and train with him. Great man! RIP https://t.co/DHRntWOvh9 — Brad Tavares (@BradTavares) February 12, 2016

My thoughts are with Kevin Randleman's family. I worked with him on men in Black3 & fought on the same cards . His energy filled a the room — Mike Pyle (@Mike_Pyle) February 12, 2016

Rest in peace Kevin. Taken way to young. Will never forget the super suplex on fador. https://t.co/X4RiO4ztdd — Erik Jon Koch (@NEWBREED04) February 12, 2016

Damn rest in peace kevin Randleman — ike vallie-flagg (@IKEVF) February 12, 2016

Randelmen was an inspiration to me and luckily I was able to be his friend as well. RIP https://t.co/ji7BVGmvcK — Jake Shields (@jakeshieldsajj) February 12, 2016

Damn rest in peace kevin Randleman — ike vallie-flagg (@IKEVF) February 12, 2016

My heart goes out to Kevin Randleman's family. I had the pleasure to train, know & watch one of the pioneers of… https://t.co/GaoViq38F0 — Roy Nelson (@roynelsonmma) February 12, 2016

So sad to hear of the passing of Kevin Randleman. I only met him a few times but he was a great man, and one of the true pioneers. R.I.P — michael (@bisping) February 12, 2016

Damn I cornered him this fight. Sad to hear the news. RIP my friend. #Repost @jakeshieldsajj… https://t.co/4tovHVvE8w — Chuck Liddell (@ChuckLiddell) February 12, 2016

RIP Monster .One of the most ferocious competitors to ever get in the cage or ring. #prideneverdie — Cole Miller (@colemillerATT) February 12, 2016

A lot of respect for the " Monster " Kevin Randelman , for what he did for the sport .

Rest in… https://t.co/h2s8S0PFPz — Rodrigo Nogueira (@Minotauromma) February 12, 2016

R.I.P Kev — Jon Bones Jones (@JonnyBones) February 12, 2016

RIP Kevin Randleman… Your smile, positive attitude & "Warrior Spirit" lit up every room & cage you walked into… TY for your friendship 👊 — Bruce Buffer (@brucebuffer) February 12, 2016

Saddened to hear of the sudden passing of Kevin 'The Monster' Randleman. Just met him last year. Man did he light up the room. RIP. — Jon Anik (@Jon_Anik) February 12, 2016

Rest in peace to a true legend, former UFC heavyweight champion, Kevin Randleman. #RIP https://t.co/dDJZyLo5KT — Michael Chiesa (@MikeMav22) February 12, 2016

R.I.P Kev — Jon Bones Jones (@JonnyBones) February 12, 2016

Yes I did, that's really sad. I met him once, was nothing but a gentleman. https://t.co/8Zf6QDPScw — Jon Bones Jones (@JonnyBones) February 12, 2016

https://t.co/yyrmvLeSYU I am so lost for words rt now you was a great friend and fighter rip my friend see you some day — Tim Sylvia (@timsylviamma) February 12, 2016

Bummed to hear that Kevin Randleman passed. I always loved watching him fight. RIP #legend #wrestling #ufc #pride — Chris Camozzi (@ChrisCamozzi) February 12, 2016

One of the greats is gone. Won the Ncaa tourney with a broken jaw #respect #kevinrandleman #ufc — Jorge Masvidal UFC (@GamebredFighter) February 12, 2016

A sad day for the world of MMA as we've lost one of the pioneers of the sport, RIP my friend!! pic.twitter.com/F6PlS2vrna — Ray Sefo (@SugarRaySefo) February 12, 2016

Damn. Just woke up to news that Kevin Randleman passed away of a heart attack. Guy was an early legend in the @ufc. This sucks. RIP. — Joe Lauzon (@JoeLauzon) February 12, 2016

I remember watching old Ohio state wrestling highlight videos in high school w this freak… https://t.co/DSrWYbmia8 — Frankie Edgar (@FrankieEdgar) February 12, 2016

R.I.P. to Kevin Randleman. One of the all time great fighters and wrestlers in MMA. — Tom Lawlor (@FilthyTomLawlor) February 12, 2016

Incredibly sad news this morning regards the passing of Kevin Randleman. A true pioneer of yesteryear. RIP. — Marc Goddard (@marcgoddard_uk) February 12, 2016

A week ago, @themonstah_ took a moment out of his day to make my son smile. Somehow, I hope Kevin knows his work made all of us smile, too. — John Morgan (@MMAjunkieJohn) February 12, 2016

Just saw the news. Rest in peace @themonstah_ Legend on the mat and in the cage. — Cody Gibson (@TheRenegade559) February 12, 2016

We lost Kevin today this man was a great guy so sad!!!! pic.twitter.com/YJGt0gJTyy — Diego Sanchez UFC (@DiegoSanchezUFC) February 12, 2016

Floored by the news of Kevin Randleman's death. Always loved watching him on the mat and in the cage. Far too young — Jimmy Smith (@jimmysmithmma) February 12, 2016

Just informed that Kevin Randleman has suddenly passed. I am so sorry 4 his family. RIP Kevin & God Bless. U were a Monster in the cage — Big John McCarthy (@JohnMcCarthyMMA) February 12, 2016

RIP Kevin be in peace! O mundo do mma ficou mais triste morreu o Kevin! Q surpresa triste ! Vai paz guerreiro ! https://t.co/r9Qpk9ZTVD — Wanderlei Silva (@wandfc) February 12, 2016

Today would have been Evan Tanner's birthday. And today we also lost the Monster. Time goes fast. Make the most of it. — Jon Fitch (@jonfitchdotnet) February 12, 2016

The world lost a great man today with the passing of Kevin Randleman. RIP my friend. #RIPMonster — Scott Coker (@ScottCoker) February 12, 2016

Met the Hammer then the Monster we were immediate brothers, Buckeyes cherish our own, Never forget he slipped backstage & couldn't fight — Mike Goldberg (@MFG16) February 12, 2016

So extremely sad to hear about the passing of Kevin Randleman. Truly one of the legends of (cont) https://t.co/LedD3Xo48T — Dan Henderson (@danhendo) February 12, 2016

Rip Kevin 😔🙏🏾 — Quinton Jackson (@Rampage4real) February 12, 2016

1 last for the night! Thanks for being there-Champ! I love and miss you! pic.twitter.com/S2sLSLWDIg — Wes Sims (@wessimsmma) February 12, 2016