A lion is called a 'king of beasts' obviously for a reason.

Lion’s are known for all of their roaring, growling, and ferociousness. They are friendly animals and truly social in their own communities. They usually live in groups of 15 or more animals called pride. Pride can be as small as 3 or as big as 40 animals. In a pride, they hunt prey, raise cubs, and defend their territory together.  

In feelings of pride, the females do most of the hunting and cub rearing. Usually, all the lionesses in the pride are related to each other as they mothers, daughters, grandmothers, and sisters. Most of the females in the pride give birth at about the same time. A cub may be taken care and nurtured from other females as well as its mother. Each pride generally two adult males. While the females usually live with pride for life, the males often stay for only two to four years. 

After that, they start their own journey or are evicted by other males who take over the pride. When a new male becomes part of the pride it is usual for him to kill all the cubs, to ensure that all future cubs will have his genes. The main responsibility of males in the pride is defending the pride's territory.