Arknights guide to LE–EX-7 in Lingering Echoes with low rarity and Chen Holungday. The “Solfège” medal is earned by completing the stage with no virtual images present from Gertrude.
Lingering Echoes guides: https://youtube.com/playlist?list=PLl6JALi7mHD0YsjTJRz9W6CrSVj6QK9QO
Arknights on Bluestacks: https://bstk.me/sX4uMNnXy
Rogue Energy: https://rogueenergy.com/?ref=I-cK2Zfl1dxBT