Totem

This is a beast of ancient origins. Once a mighty sea dweller, he became land locked hundreds of years ago due to his own greed and arrogance. 

The Totem Diver was drawn to his giant lake prison because of the abundance of totem poles that had been thrown to the bottom ages ago as a result of a horrible societal downfall. They used to be a source of food for this creature, but now they stand swaying with the currents like watery tombstones, and he as their silent protector.

After so many years of solitude Totem may never accept another sentient sea beast for companionship, yet has become so accustomed to his life that he fears leaving the lake.. that is, if he could get up the steep rocky walls surrounding him.  

For now, he's content (sort of) with his little buddy Tito, two odd landlocked sea monsters learning to grow together!