Hercules is technically Ariel's cousin
Hercules is technically Ariel’s cousin!
According to Greek mythology, Ariel’s father, King Triton, is the son of Poseidon, which would make the sea god Ariel’s grandfather. Poseidon’s brother Zeus is the father of Hercules, so Herc and Triton are first cousins. The child of your first cousin is your first cousin once removed, therefore Hercules and Ariel are first cousins once removed.
Hercules and Triton’s cousinly relationship is confirmed in (this episode of the Hercules cartoon series) - keep an open mind though, Triton looks NOTHING like he does in The Little Mermaid.