You can't really get around Palings. That's basically the point in time where the boss gets to wail on you why you have to go defensive with buffs and healing.

Yiazmat doesn't really pull the Paling thing on your party, instead he spams an instant death spell, a few really powerful super attacks, and his normal physical attack is brutal. His two biggest pains in the ass moves is that at half health, his defense rises dramatically and damage caps at 6999hp, and when he's down to about 20 life bars, he begins using Growing Threat that doubles his levels and makes him far more lethal and difficult to hurt. He also likes to cast Reflectga on your party when he's low on health. He likes to buff himself as well with Regen being the most dangerous since he can literally recharge millions of HP in a few seconds, so make sure to dispel his ass ASAP.

Yiazamt's biggest issue is that his high health makes the fight incredibly tedious and can take forever, especially since you can actually leave the battle at any time and backtrack to a save point and as long as he doesn't have the regen status on him before you left, his health will remain the same. I mean I left after I got him down to his last 10% of health and ended up completing several more Mark Hunts and getting a few more items in the Bazaar.

It's possible to beat him in under an hour but requires a pretty specific strategy, maxed levels and multiples of some equipments as well as a fully charged Dark Matter.