The Paradox is an event in Shifters. The King of Bilandria had a magic lyre that belonged to the Ancients and could only be played by the Ancients or one of their children. It had the power to turn goods things evil and vice versa. Zash Mitra led the Bilandrian Inquisition in an attack on the king's castle, but the army was driven back by Alleron, who chased and killed Zash Mitra.
However, the attack was only a diversion meant to give Daria enough time to reach the lyre. When she played it, the good kingdom of Bilandria was turned into a dark, twisted mirror of itself, full of hate and suffering.
Alleron returned to Bilandria and slew his sister Daria. When he played the lyre, the Paradox ended and Bilandria was returned to normal.