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