User blog comment:Ultrahi/About raid battle/@comment-28263903-20160421050112

I believe that getting as many 7 stars can make a big difference in the strenght of your squad. A 7 star unique not only has better and stronger skills, they have higher max stats and and a potential extra skill can really help your squad. Then there's also sphere factor (equiping 2 on all unique), imp factor and squad set up (maintaing BB spam/mitgation and no redundant skill sets).