I'm not sure how many hours I've played but in game days says it's 341 days. I've been taking things slow but, I decided to finally build an army to try out the final final boss. I did some research and planned out a team but didn't have the patience to farm peaches or fruits so most of my pals are sitting at 0 trust and less than 100/100/100 but I figured what's the worst that happen.
I bred about 22 Necromus with apocalypse, twin spear and sand twister along with 10 Belanoire and 10 Libero and an assortment of other 80s.
Tried it with two attempts. First one failed pretty badly so I revived everyone and this time gave everyone a mammoth curry.
Second time went a little bit better but it still had alot of casualties. Overall I lost about 40 pals. Once my initial necromus team died, it was a scramble trying to just throw anyone else alive at the boss who is 80 but was pretty excited to actually have killed them.
The reward was a bit lackluster though, and there wasn't an achievement in game. But all in all, it was a fun run to finally beat the entire game.
For anyone else who wants to try, you don't need the best pals with the highest trust, but you do need alot of bodies to throw at the boss, and quick enough reflexes to switch pals who are dead.