Taken from the SE forum - http://forum.square-enix.com/ffxi/threads/5774
New Trigger Conditions for Notorious Monsters
•Trigger conditions for following notorious monsters will be adjustedto spawn by trading specific items to the “???” in the respective area.
Fafnir / Nidhogg: Dragon’s Aery
Behemoth / King Behemoth: Behemoth’s Dominion
Adamantoise / Aspidochelone: Valley of Sorrows
- The ”???” will respawn a minute after the battle is over.
- The NM will despawn if unclaimed for 90 seconds at the spawned location.
- The feature wherein the level of these monsters will increase after battling them for a period of time will remain unchanged.
•How to obtain the trigger items:
Fafnir: Treasure from “Early Bird Catches the Wyrm”
Nidhogg: Treasure dropped by Fafnir
Behemoth: Treasure from “Horns of War”
King Behemoth: Treasure dropped by Behemoth
Adamantoise: Treasure from “The Hills are Alive”
Aspidochelone: Treasure dropped by Adamantoise
* At least one of these items will be dropped in every battle.
•The treasures dropped by the following notorious monsters will be adjusted as follows:
Fafnir : Wyrm Beard removed
Nidhogg : Drop rate of Wyrm Beard decreased
Behemoth : Behemoth Tongue removed
King Behemoth : Drop rate of Behemoth Tongue decreased
Adamantoise : Adamantoise Egg removed
Aspidochelone : Drop rate of Adamantoise Egg decreased