Bosses are unique, significant enemies in the Kingdom Rush series who only appear in specific levels and are much more powerful than other regular enemies. They are identified by their distinct physical appearance, almost always being much larger than any other enemy present in the level. Bosses only appear during or after the last wave of their respective stages. The presence of a Boss also causes the stage music to change in most games.
They typically have extremely high HP, extremely high attack damage (with area damage also being common), and Slow movement speed, although there are exceptions to this. Bosses also tend to have one or more special abilities/attacks that they use in battle. In the first three games, all Bosses cost 20 lives if not stopped, ensuring defeat unless the player has used a Heart Box item from the Shop. In Vengeance, this is changed so that Bosses cost infinite lives if not stopped, causing a defeat regardless of what items the player uses.
All Bosses are immune to any instant kills or only take a set amount of damage from them; status effects that hinder or stop mobility also tend to have a reduced effect on Bosses. However, most other status effects will affect them normally. The defeat of a Boss typically triggers the death of all other enemies automatically, but not always. This is on a case by case basis. All Bosses also award an Achievement related to their defeat
For boss-like enemies in Endless Challenge who taunt and support your enemies but don't actually go on the battlefield, see Endless Villains.
