Here is the full list of all 29 Scarlet Maiden achievements.
Slay 200 enemies in one run
Completer the quest ‘It’s a Strap’
Level Roman to level 5
Level Faelina to level 5
Complete the quest ‘Green Delight’
Defeat Queen Lily
Complete the quest ‘Magic Flute’
Defeat the Grand Archivist
Level up to level 50
Gain 100000 sin total
Level Bruce to level 5
Slay 100 enemies in one run
Find 50 items in one run
Gain 15000 sin in one run
Defeat the Earth Mother
Earned after 10th run
Complete the quest ‘Masquerade’
Find 20 items in one run
Level up to level 10
Complete the quest ‘Steamy Contraptions’