Bosses are an important part of the game. They use BP just like Fragment Battles. When there is a boss available, yours or one found by a friend, a red flashing "Faerie Sighting" banner will appear on the main base page. So far, all bosses have been available as part of an event. Check the Event page for what is currently available.
Bosses come in two varieties, a regular version that you will encounter by exploring and an arousal version that has a low chance of spawning after defeating a regular boss. Arousal versions are considerably stronger and drop much better rewards (minimums being Rares). An important note, do not finish another player's boss while you have one of your own waiting. Only one boss can be attached to any player's name so by killing their boss you have stolen any chance of an arousal version spawning.
The best strategy for defeating difficult bosses is to repeatedly use a small (usually 3 card), low cost deck of your best attack cards. There is no penalty for failing so this method eliminates the weaker cards that would be rotated out. Your best cards will have a high attack to DC ratio, not necessarily a high DC. Since strong bosses will usually one hit KO you, recovery and defense skills are mostly useless.
There are also boss battles as part of the story line. If they are defeated within a certain time limit, a greater reward is given, usually including Gacha Tickets.
Zone Guardians from the end of vanilla exploration zones are another version of bosses. Their card is a guaranteed drop.
These cards have been bosses in the past. The cards and their shiny versions are very rare drops. To see what bosses are currently available, check the Event page.
The following is an incomplete list of possible drops. The chances of certain drops depends on the level of the boss and possibly your contribution to the fight. Every contributor to the fight will get one card. The player who found the boss will get a second card and, if someone else finished the battle, that player gets an extra card too.
It is possible to get Boss cards from defeating the regular boss, but it is an extremely low chance.
|Regular Boss Rewards|
|Arousal Boss Rewards|