Flow Like the Stream (Merciless)

ほの暗い沼の底から is an Advent Stage that consists of a boss fight against 497. This stage has no known schedule. When clearing this stage, the player has a chance to unlock 532. This is a No Continues stage.

Battleground

 * 2 Those Guys spawn after 6.66 seconds200f, with a delay of 3.33~5.33 seconds100~160f.
 * 1 Scissoroo spawn after 10 seconds300f.
 * Infinite The Thrillerz spawn after 33.33 seconds1000f, with a delay of 26.66~33.33 seconds800~1000f.
 * 3 The Thrillerz spawn after 93.33 seconds2800f, with a delay of 13.33~16 seconds400~480f.
 * 3 The Thrillerz spawn after 120 seconds3600f, with a delay of 16~20 seconds480~6000f.
 * 3 The Thrillerz spawn after 140 seconds4200f, with a delay of 10~16.66 seconds3000~500f.
 * 3 The Thrillerz spawn after 233.33 seconds7000f, with a delay of 8~14.66 seconds240~440f.
 * 1 497 spawn after 0 seconds0f, as the boss, once the base is at 99%.
 * Infinite Those Guys spawn after 0 seconds0f, with a delay of 12~14 seconds360~420f, once the base is at 99%.
 * 1 Scissoroo spawn after 10 seconds300f, once the base is at 99%.
 * Infinite Scissoroo spawn after 0 seconds0f, with a delay of 48~52 seconds1440~1560f, once the base is at 99%.
 * 2 The Thrillerz spawn after 0 seconds0f, with a delay of 2~4 seconds60~120f, once the base is at 99%.
 * 2 Scissoroo spawn after 0 seconds0f, with a delay of 28~30.66 seconds840~920f, once the base is at 75%.

Reference

 * https://m.gamer.com.tw/forum/C.php?bsn=23772&snA=15795&bpage=1&ltype=