Bosses are enemies that have higher attack points and HP than regular enemies. When you enter a boss alone, the health of the boss when you enter the boss arena will be normal. When you enter with 2 or more players, the bosses' health will increase. When a person dies during the alien wave, the bosses' and aliens' health will revert back to the amount of players alive in the wave. However, if a person dies during a boss battle, the health of that boss will not revert backwards thus making it harder for you to kill the boss. Upon defeating a boss, the player is granted with a large amount of gold and some mithril, but though it is only given when you play in Online Co-Op. The amount of mithril dropped varies from boss to boss, and it is not guaranteed that you will always get mithril. Please note that Mithril drop rates decrease until 12 a.m. CDT, when it resets. In SW2, you earn mithril 100% of the time for 5 times a day.
The gold given is influenced by factors such as:
1) The amount of players in the boss battle
2) The amount of times a boss has been killed during that day (every time the same boss is killed by the same player in one day, the gold drop-rates for that person for that boss are halved)
3) Gold bonuses in equipped items
4) Gold pickups from aliens
There are 3 bosses available in Single-player, and 6 bosses in Multiplayer. Note however that the first three bosses in multiplayer are the same as those in Single-player mode. In SW2, there are 5 bosses for Single-player and Multiplayer.
Here is a list of current bosses:
Single player bosses in SW:AI:
Multiplayer bosses in SW:AI:
Bosses in SW2:
After you finish the initial wave of aliens, the number of surviving players will determine the amount of health for the boss, but it is unclear by how much. Here are the estimates:
1 player entering the boss fight: Boss HP 100%
2 players entering the boss fight: Boss HP 150%
3 players entering the boss fight: Boss HP 200%