Hard to explain as we don't know yet. But we will learn in episode 15: as for the snake, the episode 15 trailer…
Eight dragons sacrificed themselves for jiu yings 8head, ninth head needs to be eaten by chiwen but he cant bc theres no one left to kill him, so ig jiu ying is little now in original form but she only has three heads for now in future she will grow bigger
And thats why they’re keeping secret about fake longshen
He has been wearing that fake identity for long time so its no surprise when he’s saying that without hesitation, he may try to hide but his feelings towards wuyi will always be shown
He knows its ofc in earlier episodes baize and chiwen was alone in room probably they have secret
I think it was real chi wen’s wish,without dragon deity world will fall in chaos, fake dragon deity is best way to avoid these and baize is also protecting him
There's a catch though. The people in the illusion are experiencing it from a third person POV so CW and LWY cannot…
Remember when shiguang and wangyan saw drawing on stone ? it was someone dancing in middle wangyan said she remembered her sister or resemled, someone said there was big spoiler xiao jiu white snake loved dizhu after she died that snake created wuyi based on dizhus face
1 
Jiling/chiwen and lu wuyi
Wu shiguang and wu wangyan