O-Negative
"The same group of friends, same blood type and same lover."
In a College for the Arts of some sort, 5 freshmen students Prim, Foon, Chompoo, Art, and Puen met randomly during the ceremony on the first day of class. One day, the freshmen were required to donate blood. They learned then that the 5 of them have the same blood type, O-negative. Prim was into Interior Design. Art was into Photography. Prim was poor while Foon was rich. Art was not so poor while Puen was rich. Chompoo, in the middle.