Attacked defences become spooked and cannot attack. Chance to spawn an undead soldier on destruction of an affected building.

Battle Boost Quality	Starting Mana	Chance to spawn Undead Soldier	Undead Soldier Level
	0	10%	Level 5
	+5	20%	Level 7
	+10	30%	Level 9
	+15	50%	Level 11
	+20	75%	Level 13

Battle Boosts overview