Before Judas took over Ari's pride, he lived in a bachelor pride with a bunch of males, Ajani being one of them. They didn't get along too well, and were prone to fighting each other. But they did respect one another's strengths.
Judas is younger than Ajani, hence his smaller size. He eventually outgrows the older lion.
Brown - I know xD I mean we know how much of a family man he is, but
that doesn't mean that he can't fight. Not to mention we get to see
Ajani in action too