Tria

Paladin Tria is a Paladin. She's the first and only female Holy Knight shown in the order.

Volume 4
She was escorting Lumachina to Faltra City but were attacked by Gewalt. She was defeated and captured by his Trap Worm but luckily Lumachina was saved and got away.

Volume 6
She was revealed to have been imprisoned in one of the prison cells by Gewalt when he gave the key to her cell to Rem.