Song of the Welkin Moon Act 4 FULL QUEST Genshin Impact. You can complete Genshin Impact Song of the Welkin Moon Act 4 quest following this video guide. 00:00 1 All Is Foretold 01:48:17 2 Dance of Death Serpent and Scorpion 02:50:17 3 Echoes of Fate Genshin Impact is a free-to-play action role-playing game developed by miHoYo.