Adirea Trinn hails from Lake-town in the Dale Lands, on the western shore of The Long Lake east of the Misty Mountains. Born in TA 2993 and orphaned at an early age, her aunt took her in and cared for her for many years, making sure she learned her manners and her letters. As there were many mouths to feed in the family on a meager income and in a very small Lake-town apartment, she wound up scavenging a bit from the scraps from the barracks and grew up running wild around the docks and under-docks with the other children. She was not afraid of speaking up to the guards when some of the older boys were set on making mischief, and wound up in a fair number of fist-fights with some of the meaner ones who thought she was an easy target. 

When Adirea came of age, her aunt was unable to continue to support her and kindly (but firmly) informed her that she would have to make her own way in the world. The Captain of the Lake-town Guard, Álarr, an old acquaintance of her parents, allowed Adirea to sleep in a back bunk in the barracks in return for running errands and posting notices for the Guards around town. He had been quietly looking out for her for many years and she was happy to be useful and have a way to earn a few coins. Having developed a skill for evading hard knocks and dealing a few of her own, she proved to be quite handy in keeping troublemakers in check when necessity arose.

With very little to her name and an interest in seeing the world beyond Lake-town, Adirea eventually made her way to the town of Dale. Álarr knew the proprietor of The Jolly Bell tavern and recommended her to his friend, allowing Adirea a way to make a small income helping around the tavern as an errand-runner and unexpected but effective strong arm when drunken, rowdy patrons needed to be hauled out the door and sent home.  

Being in Dale meant being in the shadow of the Lonely Mountain and Erebor, the vast underground home of the dwarves. Every so often, dwarves would end up at The Jolly Bell on their way to-or-from Erebor, and Adirea would listen to their tales of mining, riches, and travels whenever she could. In her spare time, she would often end up in the Dale Crafting Hall, watching the artisans and crafters work at the benches and forges and dreaming of adventures in faraway lands. 

She wound up befriending a few of the dwarves that frequented the hall and the tavern and learned a bit of forgework and metalsmithing. It was one of those friendships that set her up for a chance opportunity to join a small dwarven caravan headed west from Erebor towards Bree-town, and eventually to the Blue Mountains and the far-off destination of Thorin's Hall. 

Eager to see more of the world, Adirea lept at the chance, and joined the caravan heading west with her small pack of meager belongings. Though they were a bit wary of her youth and had doubts about her usefulness, she was determined to prove them wrong. She persistently aided them by hauling equipment around to make camp and doing rounds on watch duty along the way, putting her strength and keen eyes to work. Her good nature slowly grew on them as the weeks went on, and they eventually accepted her contributions and presence among them. She also became thoroughly interested in their prospecting work, and by paying close attention managed to pick up a few of their tricks and techniques for finding ore in the rocks as they traveled.

In the Misty Mountains, their party was briefly waylaid by a goblin raiding party. Despite her inexperience with true combat (but having a lifetime of encounters with troublemakers and drunken, rowdy patrons spoiling for a fight), Adirea managed to knock a couple goblins out cold with a few good swings of her fists, which earned her a bit more respect from the dwarves. 

Having deemed her an even more worthy companion after the scuffle, they gifted her a bit of spare chain mail and some tough, metal-banded gloves. She treasures these both and generally keeps them on or close to her person at all times, and has been picking up some extra martial techniques from the other guards since then.

The caravan eventually reached Bree, and will soon set off towards Thorin's Hall. It is likely that Adirea will follow them there and will then tag along on other dwarf expeditions when welcome. She imagines that she'll end up back in the Dale Lands at some point, but is in no rush to return there.