The Legendary armour is considered the strongest equipment in Dragon Quest IX and consists of 6 parts.
The 6 parts are dropped by Grotto bosses and need to be upgraded with an Alchemiracle. Here is a list of Bosses that drop the Specific items:
Excalipurr- Victorius armour
Hammibal- Hallowed helm
Sir Sanguinus- Brain drainer
Nemean- Invincible trousers
Trauminator- Hero`s boots
There is a debate about whether apprentice gloves (Shogum drop) or vesta gauntlets (equinox drop) is the arm piece of legendary equipment.
The equipment above needs different orbs to fully upgrade it to the Legendary armour.
The Legendary armour has the ability to restore HP and MP by simply walking.