Despite the Knight being on the cover and the game being called Hollow Knight, the Knight is actually not the Hollow Knight. The Hollow Knight is your "older brother". The ages of characters are not confirmed but the community agrees that The Hollow Knight is older than the Knight. The Knight is also known as "Little Ghost" by another character who goes by the name of Hornet, The Knight's half sister. The Knight is made up of Abyss, which we will get into later.
The game begins in a small town known as Dirtmouth, after doing the tutorial in the Howling Cliffs. This small town is above the Kingdom of Hollownest, where most of the game occurs. To see the map, press here "Hollownest Map" or press it at the top of the screen.
When you reach Dirtmouth, there's an npc named Elderbug(Left-most image), who warns the Knight to be careful if he decides to head down the well, into Hollownest, as creatures who go there turn mad and travellers are robbed of their memories. Once you explore the Forgotten Crossroads enough, you will find Sly(Left-Middle image), who will return to Dirtmouth and become the shopkeeper, and Quirrel(Right-Middle image), an adventurer exploring Hallownest as well. Iselda(Right-most image) will move in by herself and is the wife of a map maker and will sell maps of areas you reach if you do not find and buy them from her husband.
Once you reach the first boss, the False Knight(image on the left), and defeat him, you will meet a witch who gives you your first magic. A blast that uses Soul, which is essentially mana.