Threads of Fate - PS

Their locations:

Legendary Sword - In the Underground Ruins. Go to the room with the lake and the floating platforms. Jump to the other side of the room to get the sword.

Legendary Shield - At Raging Mountain, after the fight with Belle and Duke, climb up one level and jump across the platforms to the right. The shield is sitting right there.

Legendary Helmet - In the Tower of Maya, go across the moving platforms with the Rabbits on them. The Helmet is right there.

Take all three of these items to Jergen in the Carona tavern. He will then make you food that boosts your stats. However, to eat the food, you need to kill a certain number of monsters and give him the monster cions. The stat boosts are as follows:

Pollywog Souffle (Requires 50 Pollywog coins) - Strength + 2
Goudon Liver Soup (Requires 30 Goudon coins) - Defense + 2
Minced Fire Blob (Requires 50 Fire Blob coins) - HP + 10
Mushroom Soup (Requires 60 Fungie coins) - MP + 10

Obviously, the best way to go is to eat the Pollywog Souffle and the Goudon Liver Soup, because you get twice the stats from them. The Minced Fire Blob and Mushroom Soup are the same stat boosts that you can buy any time. You can get the HP and MP stat boosts elsewhere, like from Hobbs's shop.

Also, one last note is that if you eat a total of 10 times, the cookware will break and Jergen will give you a Platinum Coin. This can be sold for 15,000G which is good for another three stat upgrages at Hobbs's shop.