The Kroks are an ancient race who stumbled upon Krokotopia when only the manders lived there. Taking advantage of the manders naive and gentle nature, soon the manders were no more than slaves to the Kroks. The manders have been enslaved for years, but there are a group of Kroks called the Order of the Fang who oppose the Krok tuts. The Order of the Fang seek to free the manders using the power of Balance magic, and through the Krokotopia storyline quests you will help them bring freedom to the manders and solve Krokotopia's many mysteries!
The Kroks invaded Krokotopia back when it was called Mandertopia. The Manders, polite and friendly, invited the tired Kroks into their homes and fed them. The Kroks, however, were greedy and started enslaving the kind Manders - taking their culture and lives and even souls as property.
Those are the evil Kroks.
Other Kroks, however, pitied the Manders and tried to help them where they could/can. They are friendly and treat the Manders as equals.
Those are the good Kroks.
Basically - Kroks that hates Manders are evil, while Kroks that like Manders are good.