- "Lady Yuna, we've been expecting you. We were surprised you decided to come so soon. Pleasantly surprised, of course. Lord Seymour sends his apologies for having left without notice."
For many years Tromell was the servant of the beloved Maester Jyscal Guado. When he suddenly passed away, Tromell served Jyscal's son, Seymour Guado, the whole time convinced that Seymour was a good person.
Tromell first meets Yuna and her guardians in Guadosalam, where he explains Seymour is the child of a Guado and a human, and with his newfound status as Maester of Yevon, will become the tie that binds the two races together.
Later on, in Macalania Temple, the party finds out the truth; that Seymour killed his father, Jyscal. The party fights and kills Seymour and shortly after this, Tromell, flanked by several Guado, enter, shocked and enraged to find their leader dead at the party's hands. Though he views a sphere proving Seymour murdered his father, Tromell destroys it to keep the incident a secret, and sends the Guado after the party to avenge his death.
Seymour eventually returns to Spira as an unsent. Ultimately, he murders almost the entire Ronso race when they impede his pursuit of the party up Mt. Gagazet, leaving the remaining Ronso despising the Guado.
- "If it would please you to harm a defenseless old man... then burn me, boil me, it matters not. Lord Seymour is gone. No lord rises to take his place. The Guado merely wait for Sin to come and finish us off. Why should I care what you do to me? If it meant rejoining Lord Jyscal and Lord Seymour... then your taking off my head would be the greatest kindness."
When the party returns to Guadosalam, the Guado have all but given up. Since Seymour abandoned them at Gagazet, the Guado have become more hated than the Al Bhed, especially by the Ronso. Tromell feels the worst, taking all the blame for what Seymour did and welcomes death as he feels he has nothing to live for.
- "We cannot ask that you forgive us... only that you forget us."
After the defeat of Sin and the coming of the Eternal Calm, the Guado barricaded themselves in Guadosalam until they decided to abandon their home and seek refuge in the Macalania Woods, intent on dying with the forest. Tromell was among them, still weighed by the guilt of his part in Seymour's genocide.
Over time, Tromell encounters the forest musicians and is soothed by their music. Refusing to let their brand of music fade with the woods, the Guado take them back to Guadosalam with them. Tromell is elected the new Guado leader, deciding to restore Guado relations with all of Spira, starting with the Ronso.
However, it is also possible, if Yuna does not stop the Ronso rebellion in Chapter 3, for the Guado to be slaughtered by Garik and the other Ronso who take their revenge. This event makes Tromell the only named character who can be killed throughout the game, albeit it is considered canon for him to survive.
Tromell's name may come from German word "Trommel" which means "drum".
- Tromell was to be a boss straight after Seymour in Macalania Temple, but was removed in the full game.