It's sad that Karo's accomplishments are largely lost to the sands of time and lost on newer MMA fans. He was in that era where many a "title shot" was promised then forgotten if you got hurt or didn't win the fight in an entertaining way and there were more "title contender" maybe fights than you could even recall.
Back when I was first strating to train MMA and the mantra was wrestling is the only takedown style that will realistically work in MMA, Karo was a big inspiration to me, and has continued to be in thinking outside the box for training submission grappling.
Karo, not once but twice (that I can clearly recall), was promised a title shot by Dana White only to have it given to someone else while he was sidelined with a groin injury and then also a back injury (if I recall correctly).
He lost a unanimous decision to GSP (in a competitive fight that saw him utilizing the Kimura to counter GSP's vaunted wrestling), and has wins over: Nick Diaz, Drew Fickett, Shonie Carter, Matt Sera, Josh Burkman, Ryo Chonon, Nick Thompson, & Phil Baroni amongst others.