Mirt "the Moneylender" (pronounced: MERT or: MEERT) was a fat, wheezing old rogue and retired adventurer. He made his fortune as an adventurer in Undermountain after a colorful career as a mercenary general. During this time, Mirt—then known as Mirt the Merciless or the Old Wolf or Lord Walrus—made many enemies all over the Sword Coast, but also a few friends, notably Durnan a fellow adventurer and Undermountain explorer.
History
Early Life
Mirt was the son of a successful Coaster, a Sword Coast trader. He grew up hearing many tales and deeds of heroism which led him down the path of becoming a fighter.
In his youth, he was a money-grubbing mercenary and this grew into a reputation as a great mercenary general of the North and earned him the nickname "Mirt the Merciless". He became quite wealthy, but grew unsatisfied with mere wealth. He actually craved peace and tranquility.
During his mercenary days, he met Durnan and the two became close companions. The two of them decided to "retire" to Waterdeep.
Undermountain
Mirt began expeditions into Undermountain during his time in Waterdeep. He adventured into the halls with several other notable people, including Durnan.
An entrance to Undermountain was found near Mirt's mansion below an alley named the Slide in the sewers. It eventually led to an area of the dungeon known as the Grim Statue. With his companions, they explored many areas of Undermountain—sometimes by choice, but other times by necessity. Some of those areas included the Crystal Labyrinth; an area of the Dark Levels known as the Lost Level, and the city-below-the-city, Skullport.
On one occasion, while Mirt, Durnan, and Asper were in Skullport, they ran afoul of the Beholder Xuzoun and his minions. The fighting woke up the elder Black Dragon Vulharindauloth from his decades long sleep, and he had to be driven off by the defenses of the city itself.
It was well known that Mirt and Durnan emerged from Undermountain in 1302 DR with a vast amount of wealth. Mirt used his share to build his mansion near Mount Waterdeep, while Durnan used his to erect The Yawning Portal tavern over the famous entrance.
Time of Troubles
During the tumultuous Time of Troubles in 1358 DR, Mirt was dispatched to secure assistance from any ships friendly to Waterdeep. This included tasks such as supplying Waterdeep with much-needed goods, patrolling the seas for pirates, warning of other naval invaders, and providing a means of escape from the city should it become necessary. The job also led Mirt to the island of Mintarn.
In the 1360s DR, Mirt briefly came out of retirement again to seek out and destroy The Black Basilisk, a ship crewed by Hosttower mages, and scattered their undead-crewed Dead Fleet. The Black Daggers pirate guild of the Nelanther Isles were so thankful they granted amnesty to Waterdhavian ships.
In 1368 DR, a halfling crime lord, and businessman of many enterprises of the Dock Ward (Waterdeep) received a sizable loan from Mirt. The ten million gold loan was to pay out the lottery winnings the halting ran in the Docks. Amazingly, every single person to bough into the game picked the winning numbers. This freakish luck was caused by Tymora's divine powers running amok across the Realms. The crime lord was ready to take on the monstrous loan and its interest in order to keep his reputation intact. The collection of coin took more than four hours of carting sacks of gold from Mirt's vaults and the rest of the day was spent in calculation of all the enchanted items, gems, and art Mirt needed to sell temporarily to refill the cash reserves. The same night, Mirt was visited by one of the Masked Lords of Waterdeep informing him of several similar gargantuan loans taken by other gambling organizers of Waterdeep. The Lords were troubled by the sudden influx of coin in the city of Waterdeep and the threat of inflation caused by it.
Post-Spellplague
At some point, Mirt was imprisoned within a magical handaxe. In 1479 DR, a Cormyrean noble stole the axe from another noble family, mistakenly believing it was an artifact of The Nine. He called Mirt out of the axe and Mirt escaped into Suzail.
In 1487 DR, Mirt made an effort to continuously thwart the scheming of Unknown, or rather from even attempting to begin his scheming. The two of them had several meetings for drinks and passive-aggressive conversations in Suzail.
In 1488 DR, Mirt came to the aid of Unknown, openly posing as a waiter and cook for several archwizards trapped inside a spellstorm in Cormyr, thereby contributing to the protection of the mythical Lost Spell.
In 1491 DR, Elminster and Mirt returned to the city of Waterdeep, both aiding the newly appointed Open Lord of Waterdeep, Laeral Silverhand, in uncovering the culprits behind a string of murders of Masked Lords. After the investigations, Mirt chose to stay with Laeral, serving as a personal agent for the Open Lord.
Current Happenings
Mirt come across some information from fellow Harpers member Renaer Neverember about an unknown group of adventurers having infiltrated a hidden base belonging to the Xanathar's Guild and saved a person from them thei clutches. Intrigued by this group of people he invited them over to an evening at the theater where he could check this group's worth in person. He offered them to join the Harpers if they managed to find a magical talking horse that gathers information for the Harpers.