Good Question. I had to go back and look at them because I barely remember the kids’ titles, let alone all the Trolls. I managed to find all but 3, so here are my guesses for them
Nepeta: Rogue of Heart
So Nepeta is a kitty scoundrel. She might have stolen the love of someone, or even “steal the heart” of the citizens of whichever moon she is on
Terezi: Seer of Mind
She is able to predict her opponents moves by knowing psychology.
Karkat: Knight of Blood
Karkat is a violent boy who kills things. So blood of his enemy, his own blood color, and blood land. Yeah, blood knight.
Tavros: Page of Breath
I feel like this has to do with Tavros being able to fly, but not as high as John??
Vriska: Thief of Light
Well, this is about her pirate days. As a thief. And I guess she steals the white piece’s stuff or ring or something along those lines.
Sollux: Mage of Doom
He heard his entire planet dying. He also found/fixed the game that started the apocalypse in the first place. And he has magic powers
Feferi: Witch of Life
Kissing people can bring them back to life. Plus she can talk to animals and wants to protect life. So yes, life witch.
Equius: Heir of Void
I guess he gets yeeted into space. Enjoy your new home
Aradia: Maid of Time
She was playing the field to make sure that the correct events happen for the timeline, so yeah.
John – Heir of Breath
With his jetpack he is able to conquer the skies. A lot better than Tavros I guess
Rose – Seer of Light
I guess she can talk to the gods, if we view Light=Gods. Maybe. Or because she is able to talk to the White Queen.
Jade – Witch of Space
She has a trans-dimensional dog monster. And she was able to master her dream space.
Dave – knight of Time
He also knows how to fight, and has mastered time travel