The petitioner is Hymms. He can be found in Mt Bur-Omisace between chocobo stable and one of the shops. He'll ask you to kill one overgrown Coeurl which terrorizes pilgrims.
About 22 000 HP
Resistant to Libra,
The enemy can be found somewhere around the middle of the Paramina Rift, just behind the area with save crystal (looking from Mt Bur-Omisace).
This monster also isn't especially challenging, but you have to kill him fast, or else he'll cast Balance and you'll be done for. Use the ordinary tactic: 2x berserk and a healer.
His attacks are: Rake, Balance - it deals damage to everyone in range equal to the difference between enemy's max HP and his current HP, Stone Gaze - causes petrify to one of your heroes.
Bounty: 1500 gil, Recurve Crossbow, Teleport Stone x2.