No actual background information is provided for either character. Sean and Ouranos are merely depicted as a pair of warriors aspiring to register and compete as gladiators in the annual Colosso competitions of Tolbi, but in contrast to most other would-be competing warriors they would actually be on track to make it to the tournament's finals without breaking a sweat; both are superb warriors, with Sean having an especially strong degree of speed and agility and Ouranos possessing great physical strength within his bulk. They are very confident in their battling prowess and believe they will win over all the other competitors, and for this they initially come across as slightly full of themselves. Their shared ultimate goal is to conquer the Colosso preliminaries, and then fight each other at the finals for the championship.
Isaac's traveling group of warrior Adepts first sees the pair in the town of Kalay staying at the inn with many other people from across Angara, and they are all part of a tour group that's on its way to Kalay Port at the eastern edge of the Karagol Sea, where they will take a ferry across the sea to the town of Tolbi to make it to Colosso hopefully in time. Ouranos, however, wasn't aware until right when he leaves with the tour group that traveling to Colosso would involve a voyage; Ouranos has a slight phobia of riding in boats because he can't stand water, and would have opted not to come otherwise, but the portion of Silk Road that bends above the Karagol Sea has been blocked off by a landslide, so travel by ferry is the only possibe means of reaching Tolbi.Sean and Ouranos, along with the rest of the tour group and Isaac's crew, boards the Tolbi-bound Ship. However, as the whole world has been undergoing startling changes beginning with the eruption of Mt. Aleph, monsters never before sighted in the Karagol Sea have been surfacing and attacking ships crossing it. This makes the captain of the ship and his crewmate Kaja reluctant to set out for a while, to Sean and Ouranos' frustration, and the two eventually storm into the captain's quarters thinking of using force to make the captain launch the ship, but fortunately the ship was about to launch right then anyway. But the monster issue still looms large, and safe passage can only be ensured if some of the warriors on the ship agree to protect it. Sean and Ouranos willingly agree to assist Kaja in defending the boat's deck during the voyage, and Sean eagerly points out Isaac's group as the warriors who should protect the oarsmen belowdeck.
The actual voyage is none too pleasant. Three separate waves of monsters attack the ship, and even when Sean and Ouranos have their hands full battling monsters such as Rabid Bats and Man o' Wars, monsters from each wave end up invading belowdecks and injuring an oarsman. But then a colossal sea monster called the Kraken climbs on board, and swipes Sean and Ouranos away with its immensely powerful tentacles, and it is up to Isaac and his friends to battle the beast outright in an intense encounter, which they eventually win to the pair's impressment. (Kaja later on remarks that if Isaac enters Colosso with Sean and Ouranos, the latter two won't stand a chance.)
If the passengers rowing on the left side of the ship are thoroughly strong and the ones rowing on the right are weak, the ship will eventually reach an uncharted island that is rumored to have buried treasure, Crossbone Isle, and the ship lands to get its bearings. Sean and Ouranos promise the passengers they will explore the isle for monsters to see if it is safe for the passengers to disembark, but since the two already promised to protect the ship earlier, they have no choice but to let Isaac's group explore. By the time Isaac comes back from his investigation, the ship is ready to depart and sail to its intended destination, Tolbi Port.
Once the ferry finally arrives at Tolbi Port, Sean and Ouranos rush to Tolbi, but they are alas too late and are unable to register for the Colosso competitions, to their great disappointment. All they can do is merely watch what they can while Colosso lasts, including the finals that Isaac eventually participates in. Afterwards, when all the festivities conclude in Tolbi, the pair try to return to Angara, but none of the possible routes are open; Silk Road is still closed off, and the ferries at Tolbi Port aren't sailing again. They are aware of the Gondowan Cave, the cave that is said to connect between Tolbi and Kalay as an alternate route, and they even try to go through it, but they don't have the ability to cross it on their own, so they return to Tolbi's inn and must stay there for an untold amount of time. If Isaac's group meets them one last time at the inn, Sean and Ouranos will inadvertently give them instructions on how the cave can be traversed to reach Angara back, saying that it can't be crossed unless they can lift boulders. This is where Sean and Ouranos' involvement in the Golden Sun series ends off.
- At Kalay:
- Sean: "We're so strong, making the finals will be a piece of cake! Then, Ouranos and I will fight each other for the championship."
- Sean: (Thinking) "We are the toughest of all warriors. We will never lose."
- Ouranos: (Thinking) "I have power, and Sean has speed. Together, we have nothing to fear."
- Tour guide: "Everything will be just fine, folks! We're just checking to make sure no one is missing!"
- Ouranos: "Well, I guess that's OK..."
- Sean: "But if anyone is missing, we're the ones who will miss out. Forget about them! Let's just get a move on!"
- Tour guide #2: "Oh dear..."
- Ouranos: "Right when we're leaving, they tell us we have to ride a boat? I can't stand boats... If I had known, I never would have come."
- Sean: "It's just a shame a man like you can't ride on a boat, Ouranos."
- At the Tolbi-bound Ship:
- Sean: "You know, my friend Ouranos here is scared of ships."
- Tour guide: "Ouranos? But he's huge!"
- Ouranos: "It's not that I'm scared. I just can't stand water... I'd rather be bitten by poisonous spiders than sail across the sea."
- Tour guide: "Hmmm. Spiders, huh?"
- Sean: "And even Ouranos is ready to cross the sea right now. Well, if we're not going now, then when are we going to set sail?"
- Tour guide: "What do you think you're going to do in the captain's quarters?"
- Sean: "Make him set sail."
- Ouranos: "And what if he refuses?"
- Sean: " In that case, we'll just have to do our best to persuade him... Right, Ouranos?"
- Tour guide: "That sounds crazy!"
- Ouranos: "That sounds great! Count me in."
- Tour guide: "I don't want any violence!"
- Ouranos: "I'm a man of my word. If I said I'll help, I'll help."
- Sean: (Thinking) "We have no idea when those sea monsters might attack again. Curses! I won't let them have their way with us any longer!"
- Sean: (Thinking, while the ship is at Crossbone Isle) "This island gives me the creeps..."
- At Tolbi:
- Sean: "Oh, no! We barely made it to Tolbi, and now we can't even enter Colosso. Why did we even bother coming out to Tolbi!?"
- Ouranos: (Thinking) "If we could have entered Colosso, victory would have been ours. Sheesh!"
- Sean: (Thinking) "Even though I can't enter Colosso, I stayed at the inn thinking I'll go watch. I've come all this way, so I may as well see what I can."
- Sean: (Thinking) "I want to see the finals, but not all the praising of the winner."