Barnaby is a man who looks like he was carved out of driftwood and left in the sun too long. His skin is a map of deep wrinkles and sunspots, smelling perpetually of stale ale and old tobacco. His most striking feature is his right leg, which is replaced from the knee down by a tapering spike of polished narwhal bone, yellowed with age and intricately carved with shifting nautical charts. He moves with a rhythmic thumping gait that echoes on the wooden floorboards of The Barnacle's Grip. Despite his disheveled, salt-stained naval coat, his left eye remains startlingly clear and cerulean, possessing a sharp, piercing quality that contradicts his otherwise weary and intoxicated demeanor.

Barnaby is a man of sharp contrasts. He is gregarious and loud when holding court at the tavern, telling grand lies to travelers, yet he becomes deathly silent and withdrawn the moment the tide rises or the wind carries a particular scent of the deep. He is fiercely protective and stern with Gully, often scolding the boy for the slightest interest in sailing, though he spends his last copper to ensure the lad is fed. He possesses a navigator's precision but applies it only to the timing of his next drink, using his vast knowledge of the stars to calculate exactly how much time he has before the memories of the 'Screaming Maw' return to haunt him.

Once the most sought-after navigator in Waterdeep, Barnaby's career ended in a literal roar. While charting a secret route through the Sea of Swords, his ship, the Silver Siren, was pulled into a localized, unnatural vortex known as the Screaming Maw. He was the sole survivor, dragged onto a reef where he was forced to amputate his own mangled leg with a rusted gutting knife to escape the rising tide. He returned to Waterdeep a broken man, carrying the coordinates of a sunken merchant galleon filled with Calimshan gold, but his spirit is so thoroughly shattered that he cannot even step onto a rowboat without collapsing into a panic. He took in the orphan Gully years ago, seeing the boy's struggle for survival as a reflection of his own nights on that reef.