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’
Earned after 10th run
Slay 100 enemies in one run
Defeat the Grand Archivist
Gain 100000 sin total
Level Bruce to level 5
Level up to level 50
Find 50 items in one run
Complete the quest ‘Masquerade’
Complete the quest ‘Steamy Contraptions’
Gain 15000 sin in one run
Defeat the Earth Mother
Find 20 items in one run
Level up to level 10