Board Thread:Spoilers!/@comment-24968347-20150223133450/@comment-44101411-20191114175259

Ursula is King Triton's sister. Ursula and Tritons parents are Poseidon and Amphitrite. When Poseidon died Ursula got Amphitrite's shell and half of the sea and Triton got the trident and half the sea. Triton married Athena and Ursula recalls having feasts. One day Athena Triton and their kids were playing in  bay with other mermaids a ship came and everyone fled but Ariel's sister got her fin stuck in a rock so Athena saved her but Captain hook kidnapped Athena and Ursula saved their music box but unnoticed by Triton  and put the music boy in her shell. King Triton banished Ursula and Flotsam and Jetsam because he thought Ursula threw Athena on the ship. So ...

Ursula IS Ariel's aunt.