As far as the Brits go Barrie McDermott was a straight up lunatic on the pitch.
But the Brit player that really stands out to me for being a genuine hard bastard & definitely one NOT to be trifled with is Jamie Peacock.
I always thought it was a real shame JP never came over to the NRL, he would've been a huge asset to any NRL squad IMO.
I still believe he was a considerably better overall player than Morley & that AM gets a lot more shine downunder because he played NRL.
But Peacock in his prime was an entirely different beast IMO.
As far as Kiwis go, if it's someone you'd want to have your back in a scrap, well it's hard to go past Monty, dude was genuinely feared in his time & he's one of the few players I can think of that had legit fight experience & fight skills while he was an active player.
But if I'm picking all time Kiwi hard bastards then I'd have to call it a draw between Mark Graham & Ruben Wiki.
As far as the Roos go, I always loved how Ian Roberts played the game, the guy just always seemed to be so angry & uber-aggressive whenever he played.
And when it came out that he was gay it just made him seem even tougher in my eyes, I mean to play that way against those players in that comp at that time all while being a semi closeted homosexual for as long as he did
That's something I can't even fully comprehend ... unreal toughness IMO.