Curse of the Sphinx bonus (Pixiv Fanbox)

Looks like the sands of time ran out for Nico as he fails to solve the riddle. After a valiant struggle he is overwhelmed by a cursed slumber as his mind is reshaped through dreams so when he awakes he is ready to serve his Sphinx lord. Did you solve the riddle? If not then you'll join the demigods in their fate.