Law’s name was taken with 18th century real-life English pirate, Edward Low. Law’s apparently infamous cruelty echoes Edward Low’s own reputation for violently torturing victims before killing them.
Law’s surname, Trafalgar, was taken with cape Trafalgar in the south-west of Spain. Its name is Arabic in origin, meaning “Western Cape”. It was a famous naval battle between the British and the French/Spanish fleet during the Napoleonic Wars, dubbed the Battle of Trafalgar. London’s landmark Trafalgar Square is named for the battle, as is a class of submarines in the British Royal Navy.
Law’s full name, Water Law, was taken with fight with Wellington, may be a reference to Waterloo, the place in where, on June 18th 1815, was fought the final battle of the Napoleonic Wars which represented the ultimate defeat of Napoleon at the hands of the Seventh Coalition. The British commander at Waterloo, Arthur Wellesley, was the duke of Wellington.
Law’s wanted poster shows Bepo appearing in the background with his head turned in the same position and stance as Usopp in Luffy’s poster.
At 26 years-old, he is the youngest individual known to ever hold a position as one of the Shichibukai.
Law uses the “smiley” style of Jolly Roger, as first seen used by his former superior Donquixote Doflamingo. But unlike Doflamingo’s smiley, his does not have a “cancel” sign across it. The smiley most likely refers to the final moments of Donquixote Rosinante, who died with a smile before he told Law to remember him smiling from that day onwards.
Although he isn’t named after him (Zoro is), Law’s escape from the attack on Flevance almost mirrors the actions of real-life pirate Francois L’Olonnais, who was shipwrecked and attacked by Spaniards. L’Olonnais covered himself in the blood of his crew and hid amongst their dead bodies in order to survive. L’Olonnais was also known to be ruthlessly cruel, mutilating body parts and internal organs with his sword when torturing victims.
Law’s birthday, October 6th, comes from his surname’s Japanese trancription first syllable and his name’s Japanese trancription since 10-6 can be derived from to-ro. He shares his birthday with Tashigi and Bartolomeo.
Law’s favorite foods are onigiri and grilled fish, and his least favorite foods are bread and umeboshi. He share dislike of bread with Donquixote Rosinante.
According to the 6th Japanese Fan Poll, Law is the 4th most popular character in One Piece, making him the most popular Supernova excluding Luffy and Zoro.