Limited Missions (限定任務) are a type of missions you can attempt that are only around for a limited amount of time. They are all accessible from the Limited (限定) tab in the subjugation menu.
A Secret Garden (秘密の花園) is one type of Limited Mission. It is sometimes shortened to SG, but this is ambiguous with the world of Spring Garden, so be careful. Alternatively, they are called a Bonus Stage (ボーナスステージ) which is shortened to BS.
A BS usually requires stamina to run through. The rewards for clearing a Secret Garden are worthwhile and the bosses are simple even for the weakest of players, so it is recommended to clear any Secret Gardens that may appear. Secret Gardens do not count as a subjugation for the purpose of quests.
A teal banner saying "Bonus Stage Appearance!" will signal that a Secret Garden was found. A confirmation box will then appear and ask if you want to go to it immediately. The red button on the left says "Yes" while the teal button on the right says "No". Selecting "Yes" will take you to the Limited-Time section of the Subjugation tab.
Secret Gardens found from subjugations have take up stamina based on the difficulty level from which they are found. The usual stamina cost is as follows.
- Elementary level Secret Gardens cost 12 or 25 stamina.
- Intermediate level Secret Gardens cost 50 stamina.
- High level Secret Gardens cost 80 stamina.
A Challenge Dungeon (チャレンジダンジョン) is a Limited Mission that becomes available after you beat E4 or E8 of an Event. They are only available during the event's time as a featured event. The 1st half challenge dungeon tends to cost
40 zero stamina and earns you a Leader Medal when completed. The 2nd half one costs 50 zero stamina and earns you a Premium Gacha Ticket.
Oct 23, 2017: Challenge dungeons don't cost stamina anymore.
Manyu Summon Stage
Using a Manyu Summon Key (強化精霊召喚キー), you can summon a BS that produces a lot of Manyus. The stages do not expire, but they cost 100 stamina. Unlike the Manyu daily missions, there is only a single enemy here which is pathetically weak.
Oct 23, 2017: This feature was added.