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