What about when it says to "fuse 99 levels of SEN"? Does that mean a lvl 99 SEN or fuse the host with 99 SENs?
It means either or will work. Heck you can fuse it with 33 lvl 3 SEN or vica versa. A lvl 50 and lvl 49 would work to. As long as you reach a sum of 99( in there levels) or more with SEN you will unlock the secret skills.
Man Those builds haven't changed much since I last played. Would thought a few had major or slight changes. Last time I played was Ultros Typhoon DLC, which was before snow was released.