Black Manta
Mere land conquest is not enough for Black Manta. He's out to rule the seven seas and all it contains, including Aquaman. Armed with unique undersea weapons, Black Manta is a dangerous threat to everything that lives under the sea.
While responsible for the death of Aquaman's son, Authur Jr., Black Manta is best known for his cool echo-y voice from the "Super Friends" cartoon.