In the anime, Pocketmonsters, Pikachu is the main Pocketmonster in the show.
He lived with Prof. Oak until a boy named Satoshi took in Pikachu as his first Pocketmonster,
a gift from Prof. Oak. At first Pikachu didn't like Satoshi, but they grew to be great friends.
Together, they fought other Pocketmonster trainers to become masters.
Satoshi had to collect badges from various Pocketmonster Gym Leaders to become better. He caught more Pocketmonsters on his journy besides Pikachu,
which also helped him become a master.
There are many great expeirences Pikachu and Satoshi went through, they were ghosts together, they were attacked by spearows, they were almost split up, and defeated all great trainers. Through these expeirences Pikachu and Satoshi grow closer and that makes them special friends.