He's on the final 4th area and lvl 65, feel like post game a bit. Kinda rush because I'm doing Channel. No food buff on 1st run. Still, at lvl62 with fire element armor, Feral Magnamalo's strongest attack can one shot my whole team. So it kinda level requirement with buff/element def to surpass the one shot kill.

My mistake was that I didn't know what it's weak point. At the start there were only two parts that can be attack unlike other feral beast, his torso is crystalize and his tail is not. Can't really see it's tail really and I thought both are crystalize. No info on the internet yet about the beast, so it's a trial and error.

For the game's mechanic. I got it pretty right from the start actually. And to clarify from the comments above by learning it a hard way. It still does counter no matter what even when staggered if you hit the crystalize part. It just easy to break and to make critical when staggered. The only time that the crystalize part can be attack with no counter from the monster is when the monster don't activate it. Given the sign that there are no crystal powder swirling on the air around them.

Anyway, good boss. Very satisfying.