i can't find mini boss at Mysterious Monuments in chapter 8. how can i find him?
The first thing you have to do - actually not to do - is not to kill the monemunts.
Set you heroes on "Stop" or "Hold" position and attack the red monument with one of the Phodom's direct damage spells (1st spell) - the golem would appear. Kill him. After it attack the blue monument with Galeoth's direct spell (1st spell) - another golem. And on the 3rd time attack the Yellow monument with Fradz's direct damage spell (again 1st) - the Boss finally would appear. Do not forget to steal his item - it is a part of Omega Set!
Gl