ABE FROMAN - Heavyweight Liddell. Cain has shown that he can be KO'd, a great sprawl and brawler should be able to win against him. Junior was good but not great.ANYBODY can be KOd, especially at Heavyweight. It's not like Cains chin is a weakness of his.
LAE -In before "if Fedor never grabbed the fence he wouldn't have won"shaqitup -He tapped Lindland.
I don't think FEdor would tbh, his weakness was good wrestlers.
A lot of people thought he lost to lindland and Arona.
I didn't say he was chinny, I said he wasn't Roy Nelson. This thread wants to know how to beat Cain, the most reasonable way is to assume in ways he had already lost or close to lost.
The Legendary One - Someone who can neutralize his wrestling like Cormier, KO him standing like JDS, has a good chin like Nelson, and mainly, match his cardio. I think Overeem on his roids could beat him since he'd be hard to takedown and unlike JDS, Overeem would make Cain pay for his takedowns. Cain also wouldn't want to clinch with him either. Of course Overeem would be gassed of it got passed the second round. Too bad his off his roids
imontoya - Fedor...a HW that lost to a middleweight (Henderson),Yes. Yes they are that delusional and it sickens me.
are you guys really that delusional??
GaryColeman -imontoya - Fedor...a HW that lost to a middleweight (Henderson),Yes. Yes they are that delusional and it sickens me.
are you guys really that delusional??
Jimmy Rustler -shaqitup -I don't think FEdor would tbh, his weakness was good wrestlers.
A lot of people thought he lost to lindland and Arona.
he lost a fight that he won by submission? wow!
i think he meant babalu, still not too smart though. 
I know OP is not asking what fighter, rather what style, but I think Travis Browne *may* give him problems.
He's got a significant size advantage and if he uses his hands to keep Cain off he can also land a few big shots (Cain has been known to get hit). His TD defense is something like 100% - let's see if it stays that way after Barnett though - and I don't like Cain's chances trying to keep Travis pinned to the cage.
a powerpuncher that can also not get dryhumped against the cage for 20 minutes. someone that can get themselves out of the clinch and circle out.
tunaburn - a powerpuncher that can also not get dryhumped against the cage for 20 minutes. someone that can get themselves out of the clinch and circle out.
A lot of fighters match up well with Cain, but what separates him from them all is his cardio. I don't think any other heavyweight can keep up with his relentless pace - nor do I think any would try to match his pace
Someone with better striking and comparable wrestling ability. Not likely to see that for a while though.
Henderson would get destroyed.
Who ever mentioned Travis brought up an interesting possibility.
The fact is circling out of the cage instead of getting pinned against it or stuck in the clinch, and circling out of the cage instead of getting pinned against it or stuck in the cling by a legit heavyweight with the most relentless pace and cardio the division has ever seen is another.
The guys pace is ridiculous, his striking is on point his wrestling is top notch and his chin is solid.. going to take a special fighter to beat him.
Prime Fedor had the striking, grappling and speed advantage. Cardio was =
I vote for a 250lb Machida. Elusive counter striker to beat the man who only comes forward.
Werdum can beat him
Werdum is awesome but he won't beat him. Cain will punch his guts out standing.
A Fedor "type" is right, I think. Someone who's just as busy but can bang and do subs. Another wrestler who can punch with crazy stamina might do it but I think a sub guy who can KO with either hand (like Fedor) would be the one to take Cain. I haven't seen anyone like this though.
It's no secret. A fast and accurate striker who can defend the takedown and make him pay for getting close.
I honestly think Werdum has nothing for Cain. I expect Cain to dominate him from bell to bell until he finishes him. Only way I see Cain losing is by KO.
JDS tagged him a couple times in the last fight and Kongo was able to drop him multiple times (not to mention JDS knocked him out already). A pure striker will likely not get a chance to KO him, so it'd have to be a Shane Carwin type, great wrestler with KO power. Sadly there is no one like that currently.