Lion

From Wikipedia:

Lion's Share is an expression that has come to mean the larger of two amounts, or more often, the largest of several amounts.

The saying derives from one of Aesop's fables, where the term is actually defined as the complete amount (all of it).

In the fable, a lion, fox, jackal and wolf go hunting, successfully killing a deer. It is divided into four parts with the lion taking the first quarter because he is king of the beasts, the second quarter because he is the arbiter of which animals get what portions of the deer, the third quarter because of his help in catching the deer, and the fourth quarter for his superior strength.

In some variants of the fable, the lion only takes three-quarters of the deer and lets the other animals fight over the remaining quarter.