My rooster WAS very very aggressive, he used to attack my leg from behind with such a force that if he missed it and hit the ground he was bleeding from his comb, he had wounds from failed attacks at my leg. I used many methods to tame him that failed, some of them are: hold him upside down from the legs for some time, pick him and move him back n forth, chase him many times, i even had to kick him with all the power i had one morning and he took off 5 feet before he landed then he coughed and i thought he had internal bleeding(i had to do that as i was defending my baby daughter that i was holding).
It took me few months of battles and lessons until i figured out what worked for mine, i isolated him in a cardboard box that he couldnt even spread his wings, i did that from 15:00 and left him overnight there and i opened up the next day at 11:00 in the morning, he had no light at all, cardboard closed and placed in a 100% dark storage room (no water no food) when i opened up he got very scared and i didnt do anything but let him go to his "lost" hens. He havent been aggressive for no reason since then (i still keep an eye over my shoulder tho)
hope it helps somebody