There are 38 Characters...that I know of.
Goku, Kid Goku, Kid Gohan, Teen Gohan, Gohan, Great Saiyaman, Goten, Vegeta, Trunks, Kid Trunks, Krillin, Piccolo, Tien, Yamcha, Hercule, Videl, Supreme Kai, Uub, Raditz, Nappa, Captain Ginyu, Recoome, Frieza, Android 16, Android 17, Android 18, Dr. Gero, Cell, Majin Buu, Super Buu, Kid Buu, Dabura, Cooler, Bardock, Broly, Saibamen, Omega Shenron, and Cell Jr.
If you factor in Gogeta, SS4 Gogeta, Vegito, Gotenks, Kibitoshin, Mecha Frieza, Metal Cooler, and Majin Vegeta.....that's how you get over 40 characters.
As for this nonsense about Grand Supreme King Kai.....you tell me how to unlock him, and then I'll believe it. Unitl then, Grand Supreme King Kai IS NOT in the game.
Death is but a door, Time is just a window,...I'll be Back!!!!!