Nautilus' old lore was that his crew abandoned him, and after an evil power caused him to be fused with the diving suit he was wearing, he begrudgingly carried the only clue (and symbol of his heavy grudge), the lost anchor of the ship, all the way through the depths of the ocean in order to seek his vengeance.
The new lore turns him into a boring sea monster that sinks ships.
All know the tales; all pay the Bilgewater tithe. Since time immemorial, Nautilus has roamed the dark waters off the coast of the Blue Flame Isles, dragging impious sailors to their doom. The armored goliath strikes without warning, his inexorable footfalls churning the waters, before swinging his enormous anchor upward to shatter mast and keel alike. He then pulls the flotsam beneath the waves to appease the wrath of the Bearded Lady.
This completely removes the tragedy of Nautilus' character, that he is a corrupted person so bent on revenge that instead of just letting go of whats weighing him down, he would carry it with him to the ends of the Earth. His identity has been completely replaced with that of a cartoon villain.
