When did the Manticores appear at 130%? Were there any problems with defeating them?

They appeared at different times. The first time, I lingered near the orange Castle, and they appeared simultaneously, I think around week 52 or 53, I don't remember. Then I retreated, sped things up, and returned to week 513. Week 523 brought the green Manticores, but the battles weren't too difficult. However, the gray Manticores appeared in week 535 (I suspect it was because I was in the starting Castle; if I hadn't been, they would have appeared earlier), and I sent 2 or 3 heroes in turn, I don't remember the sequence or who the Manticores were :) but the battles against the gray ones were very tough, and there were losses. The main goal was to start assembling Cyclops, Rocs, and something resilient in the army, to eliminate the Ballista, usually with Dragonflies or Rocs, flying in and out of the Castle, to deal with the Archers (with Archers or something with high attack and haste), and also with flying units (slow them down and shoot them down), a mix of everything mentioned. In some cases, I had to somehow prevent the opponents from casting the spell that destroys the Castle; otherwise, when they break through the wall, it's impossible to kill, for example, Unicorns, without losses. But if you have the "Archery" skill, everything will be much easier. I didn't have it at 130%, but now I have it at 200%, it's a must-have.
But the point is that, according to the author, people at 160% were already going to the Necropolis around week 611 or 711. I went later because I didn't know.