LogFAQs > #942012034

Its a bit of a grind to max out the skills for that trophy in just NG+ (especially if you do the Shura ending which locks you out of the "endgame" areas with high exp enemies) whereas if you do 4 full playthroughs youll spend much less time mindlessly grinding at the end, plus you get more experience the higher NG+ level youre one. Also each playthough only gives enough Lapis Lazuli to get 2 of the Lazulite tools and if you do Shura on your 2nd playthough youll get locked out of getting enough.

Theres also a trophy for defeating every boss on the same save file so youll need at least 3 playthroughs on that save file since you didn't get the 2nd Owl fight on your first run and cant fight him on the Shura path + you need the Shura exclusive bosses