Cartoon Network (ended 2005)
Hi! Cougar did recognize Kazuma, even though he pronounced his name wrong. While they were chasing him, Cougar looks in and seems sort of shocked, and accuses, "Hey, you're Kazuya!"
(Then of course the obligatory, "It's Kazuma!")
If you remember, in the end of episode three, Cougar is staring off and Mimori approaches him about Kazuma, asking if he knew something about "that Alter user". Cougar just shrugs and grins, saying that he looked like someone he used to know, "But I guess it wasn't him!"
I think their relationship is sort of brotherly, kind of like younger brother/older brother, even though they aren't really related. Cougar was sort of Kazuma's friend and mentor. Kazuma flashed back on when he was little and Cougar was much younger in the episode "Shell Bullet", and also remembered Cougar's words to him in the episode "The Stray Boy".
I hope that helps.
I think they are somewhat related because both of them know how to use shocking first bullet. I think they were pupils of some alter user that taught them how to truly master their alter.
Well, in the Straight Cougar episode, Cougar says something around "We were just strangers that hung out with each other"(Or something like that) after Kazuma says he just disapeared. But clearly stating that they were not realted. In the flashbacks they showed it always seemed they were brother-like, but when the show up in each other's lives they seem to be different.. as they fought quite ruthlessly in the Straight Cougar episode.