Are you talking about Hokage Minato's Skill Breaks? If you are he only has one and all it does it change the "Defender of Konoha" ability which gives 40% resistance to the entire field from "5 Rounds" to "Permanently". It isn't worth the 50 fragments it costs.

If you want to get your H Minato to four stars it will be very expensive and now would be the best time to do it. You should only do it if you use him a lot, otherwise just spend it one something else.