Tromus was originally a pupil under Lord Demanitus, along with two others who traveled with their lord on his journey to study and find the legendary sun and moon drops. At one point on their journey, however, he, Sugracha, and the third pupil decided to betray Demanitus by siding with Zhan Tiri as her new loyal servants, after they freed her.
At some point, after Demanitus defeated Zhan Tiri and sealed her away, Tromus had become the inner keeper of the House of Yesterday's Tomorrow, while living under the guise of Matthews.
Role in the series
When Rapunzel and a few members of her traveling party knocked on the door of the House of Yesterday's Tomorrow, so they could have shelter from the storm and also because of a tree which fell down and blocked their caravan, Matthews answered the door and let them in the house. But, Cassandra was suspicious of him because he was letting them stay in his inn without asking for payment.
After the gang defeats their mirror doppelgangers, they attempted to leave the house, but when they found that the storm had gotten worse, they stayed for the night and it's also revealed that the tree was chopped down intentionally.
Next in "You're Kidding Me!", he planted The Old Top of Time in the nursery. Cassandra found the toy and turned it on, it turns her and Lance into children, and Shorty a baby, he tells Rapunzel that the only way to reverse it is to spin the top backward and they have one hour to find the top or they'll stay as children forever. Also, he did tell them that they could keep things the way they are, and that his house could become their new home and they would become a happy family.
After Rapunzel and Eugene got their friends back to adults, he has been watching them, seeing as that the mirror and the top have failed, he vows to his master that he will keep the "Sundrop" (Rapunzel) in the house forever.
He appears again in "Rapunzeltopia". Matthews has trapped Rapunzel in a dream world where she is having a perfect life of her coronation week and reveals to Eugene and Lance that he is Tromus, a servant of Zhan Tiri, explaining that his master needs the Sundrop power. Once Rapunzel accepts the illusion, the magic vines will surround Rapunzel completely, she'll be trapped in the dream world forever, and the Sundrop's power will belong to Zhan Tiri. However, Rapunzel's subconscious mind starts to tell her the only way to escape the dream is to touch the Black Rocks, and when Tromus notices, he goes in the dream world as Eugene in order to convince her that she doesn't have to make any big decisions, she even accepts his marriage proposal, and the Sundrop power is nearly in Zhan Tiri's grasp.
When the time has come for her coronation, Rapunzel was about to be crowned, but her subconscious reminded her that once she is crowned she'll be trapped in the dream world forever, so Rapunzel realizes her mistake and refuses to put on the crown, Tromus appears again to stop her by changing her dream into a nightmare, Rapunzel realizes this is her mind and she can control everything in her mind and uses her mind power to transport them to the cliff, where she touches the black rocks Rapunzel succeeds in touching the black rocks. and wakes up. The house started to crumble and everyone escaped, the house turned into sand and so does Tromus, but not he before vows that it isn't over.