Old Rivals, the side-quest in Dead Dunes area of Lightning Returns: FF XIII is the first quest you should complete after Adonis’s Audition, because it doesn’t have specific requirements regarding the time when it becomes available, or other quests that must be finished.
Old Rivals also includes His Wife’s Dream side-quest, meaning that when you play it you will complete two quests instead of one.
If you aim to finish all quests in Lightning Returns: FF 13, then you should start Old Rivals the moment you reach Ruffian, after you complete Adonis’s trial and after you meet Fang (main-quest 4-2: Aspiring Bandit).
Throughout the following Lightning Returns: FFXIII walkthrough, we reveal all steps you need to follow up to the point when Old Rivals ends.
Description: “Tobias is a wealthy merchant who runs several shops across the Dead Dunes. But the lack of competitors out in the desert means his selection is poor and customer service worse.”
Location: Dead Dunes
Rewards: 500 Gil, Maximum HP + 50, Magic + 2, Strength + 4, Snakeskin Hat Adornment
So, the first thing you have to do for this side-quest is to activate it, by finding the client named Tobias. Assuming that you are in Ruffian, head outside the small camp, and locate the red Cactuar statue.
Turn around and you should see the General Store. The owner of the store is your client, and he wears a cowboy hat.
Talk to him to activate Old Rivals, and if you didn’t activate the Ruins North Gate Warp Point by examining the red Cactuar in Giants’ Sandbox; then get ready to walk a long distance south.
If you activated the warp point, then use the Cactuar statue in Ruffian and teleport to Ruins North Gate. If not, open your map and head south to get to the said destination. As you stay close to the Temple Ruins North Gate entrance, look for a small merchant near his stand. He is Ramon, and you have to talk to him first.
When you approach Ramon, you will start another side-quest named His Wife’s Dream. Completing His Wife’s Dream is mandatory if you want to finish Old Rivals.
Follow our His Wife’s Dream quest walkthrough, and find the item for Ramon, then talk to him, and teleport back to Ruffian where Tobias awaits. Satisfied, your customer will hand you all rewards and the current quest ends.