Thinthil is originally from the Kingdom of Dale, more specifically Esgaroth. His parents were poor fisherfolk, and their relationship was unstable. When he was three years old his father injured himself in an accident, losing an arm. Unable to provide for the family, Thinthil's father turned to alcohol and violence while his mother disappeared without a trace. A few years after this (around the time he was seven), Thinthil ran away and became a street rat, surviving by picking the pockets of the citizens of Esgaroth. This landed him in jail quite a few times over the three years he lived like this.

At age eleven, Thinthil made the bold decision to attempt to rob a wealthy individual who lived on the outskirts of town. He almost succeeded but was caught while fleeing the premises. As it turned out, he had tried to rob the head of Esgaroth's Smuggler's Guild. Impressed with his skills, he hired Thinthil as a low-level associate of the guild. Over the next several years, Thinthil would work his way up through the ranks due to his talent, aptitude, and a series of unfortunate deaths among the higher-ups of the guild. By age 17, he had become the guild master's right-hand man, a position of exceptional power never before held by one so young. He served in this position happily for many years, spearheading ambitious endeavors that brought great profit to himself and the guild. After the great success of these risky endeavors, he took the title Highroller, which was the only name most of the Guild and the Guard knew him by.

Several years later, and the guild had been brought down by a new Officer of the Guard from Dale. All of the high-ranking members of the guild were caught and hung... but Thinthil was nowhere to be found. Indeed, not even a mention of him was found in the guild's records, for he had been far too cautious for that. The only thing belying his existence was his signet on the records of operations he launched... a knife through a die.

He had escaped the purge by moving to Bree, where he had planned on starting a new criminal enterprise. However, a series of events and new friends led him to look back on his past, and he found that he hated what he had done and decided to adopt a new lifestyle. Now Thinthil works to atone for his past actions by providing aid wherever he can while trying to ensure that he can keep the new life he's found.