ill explain how i got it and maybe it will help some people. I went to klassic towers and did the survival tower on very easy because each fight only lasts 1 round. One of the guesses for how to do it was 100 finishers, and since you need 100 brutalities for another trophy, i started with those. i had 28 brutalities before i started, and killed jade with a brutality over and over until i had 101 brutalities, cause the trophy didnt unlock at 100. so i did 73 brutalities. then i started doing fatalities. i was at 90 before i started and the head wasn't awarded until 135. so i did (Excluding the 15 or so towers i did before the calculations which may add a few fatalities) 73 brutalities and 45 fatalities for a total of 118 finishers. so its definitely not 100 finishers, its definitely not 50 brutalities like powerpyx is saying. It must be a mix of the two that does it. for example, maybe its 25 brutalities and 50 fatalities or something like that. it could also be completely random, but i don't think NRS would do it that way. hopefully this helps a little bit.