The time changes in the game from day to night and night to day, and I decided that this could be used to complicate life... The first:
Step number 1 - Sunny time all monster low down effect defense x0.25 and low down effect attack x0.50 but have no changed exp;

Step number 2 - Evening begins all monsters receive effect increased attack x1.5 and effect defense x1.25 no changed exp;

Step number 3 - Night has come all monster have increased attack x2 and defense x1.50 bonus exp x1.5;

Step number 4 Full moon/Event(very rare) blood moon - all monster increased attack and defense (normal moon x2.5 attack/x1.75 defense, exp bonus x2), (blood moon x3 attack/x2 defense, exp bonus x3);

Step number 5 Night time become back step 1.

Moon phases are shown at the top of the game screen when night falls.

if you have a better suggestion for my post, suggest in the comments