Leviathan

The leviathan was a huge whale and child proxy of the Earthmother of the Moonshae Isles.

Description
A great black skinned whale, the leviathan was larger than any whale naturally found on Toril. Fully 360 ft (109.7 m) long, the beast's tail was 60 ft (18.3 m) wide and the creature had a mouth full of razor sharp teeth.

Abilities
The leviathans was mortal and could grow old and die like any other natural creature. Though it was immortal in a sense, it's spirit would be reborn in time after it died.

History
The behemoth slumbered for centuries until awakened by the Goddess in 1345 DR.

Death
The leviathan was killed by several poisoned poles attached to the ships in which Kazgoroth, disguised as Thelgaar Ironhand, led an army of northerners against the Ffolk of the southern Moonshae Isles.