Level Sync: 20

Boss: Yagudo Bouncer

Prey:  Yagudo

Kills needed for boss: 15

Notes: Follow the arrows killing all the Yagudo. The bats will aggro you as well. 

Level Sync: 30

Boss: Yagudo Scout

Prey:  Yagudo

Kills needed for boss: 20

Notes:  Follow the arrows killing all the Yagudo. The bats will aggro you as well. 

Brass Door answer by day

Firesday (Left)->Earthsday (Right)->Watersday (Left)->Windsday (Right)-> Iceday (Left)->Lightningday (Right)->Lightsday (Left)->Darksday (Right) 

Level Sync: 40

Boss: Yagudo Scout

Prey:  Yagudo

Kills needed for boss: 20

Notes:  Follow the dotted line with sneak/inv. Kill the mobs in the solid circle then follow the dotted line back up for the boss. The bats will aggro you as well.

Level Sync: 50

Boss: Yagudo Scout

Prey:  Yagudo

Kills needed for boss: 10

Notes: Trade the npc Yagudo the beastcoin to get teleported. Kill the Yagudo as you follow the line afterwards. The bats will aggro you as well. Can usually skip a few by the end. A last little dash to the boss usually works well.