Simplify the following text for a Grade 7 native English-speaking person.
Original: In the show , fifteen-year-old Sokka is a warrior of the South Pole 's Southern Water Tribe , a race of people who can control and manipulate water .
Simplified: In the show , 15-year-old Sokka is a warrior of the South Pole 's Southern Water Tribe , a race of people who can control water .