Why is this the answer?

The answer is sword because this clever riddle uses amazing word pictures to describe one of the most famous weapons from fairy tales, knight stories, and history books. A sword is a long, shining metal object that brave heroes and powerful kings carried a long time ago. Let us look at each clue to see how it perfectly describes a sword. The first clue says, "A dragons tooth in a mortals hand." A dragon's tooth would be a very long, sharp, and scary thing. The long, sharp blade of a sword looks just like a giant, dangerous tooth! The "mortal's hand" is simply the human hand that holds the sword. The riddle is trying to trick you into picturing a real dragon, but it is actually making a grand comparison about the sword's sharp, dangerous shape. The human holding it is the one who chooses how it is used. Next, the riddle says, "I kill, I maim." This is the part that talks about the sword's main job in olden times. In stories of knights and castles, the sword was the essential tool used in battles and serious fights between warriors. The words "kill" and "maim" are grown-up words that mean to injure or decide the end of a life. The riddle means that the sword was the important weapon that decided who won a great battle and who lost. It reminds us that a sword is a serious object used for fighting, not for playing games. It was a tool that carried a lot of power for those who held it. Finally, the riddle ends with, "I divide the land." This is a tricky clue that talks about history and kingdoms. Swords were the key tool used in wars between different kings and countries long ago. When one side won a big battle with their soldiers and swords, the map of the world would change. One powerful kingdom might take control of the land from another kingdom. So, while the sword itself did not draw a line on the map, it was the weapon used in the major fights that decided who owned the land, making it a symbolic tool for "dividing the land."