Aggression between roosters isn't necessarily a sign of aggression towards people.
It might be an attempt to rearrange the rank. Might be the case if it's between the two only and Ozzy is not picking fights or beating on other roosters. If Ozzy wins, it is possible for things to become peaceful again however it is normal for the new winner to be a bit hard on the loser for a while but things eventually calm down to before.. as long as there are no further attempts at rank rearrangements. Basically much like a hen fight but roosters take it to a higher level.
If Ozzy is also being hard on other roosters, he may be one of those that just cannot stand other roosters being around and there isn't much one can do about these other than isolation/culling. (I cull these but that is a personal decision, not a recommendation. I like things being peaceful and easy in the flock)