As I say, he's a contradiction.
By all accounts he hit the grog pretty hard in the first half of his career, but would destroy teammates for perceived flaws.
To this day he still holds grudges with lots of ex-players / teammates / managers, which isn't normal behaviour for a man in his 50s.
But catch him on his good day and you can tell he's mellowed and is maybe even a little embarrassed at some of the types of behaviour that his driven nature resulted in. In the right company, when he's not putting on a show for Sky Super Sunday, he looks like good company.
No doubt his Irish teammates were, on average, at a lower level to his club colleagues. But there was a unique team spirit, for a few decades, in that group that in their own way drove them on as a cohesive group. To a large degree Keane was a lone wolf outside of that group dynamic. But he contributed so much that it wasn't an issue. Players treated Roy as a special case and walked on egg shells at times.