explanation (not mine)

i took this b4to from GaYane bc it explains this so welll

For those who didn’t understand the meaning and the ending of this story:

In the end, Todd disappears taking all the sheep with him. Heartbroken and unable to cope, Dennis throws himself from a cliff into the darkness.
This manhwa is full of symbolism and it contains some references to the Bible. This story is not about love, it’s something much deeper. So this is how I interpreted this story. Sorry, it's a little long.
Todd is the wolf(coyote),representing the devil himself, while Dennis is the opposite-naive, innocent, like a sheep.

Early in the story, the farm owner warns Dennis to “trust nothing except the sheep” which can be interpreted as to trust only what is pure and innocent(In the Bible, sheep are seen as symbols of innocence ).The farm owner already knew that someone or something was in the mountains, who seduces men and takes away their sheep.
Todd lures Dennis in with love, but his true goal was the sheep and more importantly-Dennis’s soul.Dennis falling in love with Todd represents him giving in to temptation. He places his trust in the very opposite of purity, despite the farm owner's warning.

In the end, Todd devours all the sheep and returns to wherever he came from (symbolically hell). Dennis is left with nothing-no love, no sheep, no purpose and devastated by that,he takes his own life, following Todd into the darkness.
Todd didn’t just take the sheep,he took Dennis’s soul as well, connecting with him through his mind and seducing him to fall from the cliff.

This is where the title "THE FALLEN LAMB" comes in. As we understood, in the Bible, a lamb represents innocence and purity. This suggests that Dennis was once pure, like a lamb, but after falling in love with a devil, he lost everything and fell-both metaphorically and literally.He was a sheep himself,eventually devoured by the very wolf he trusted.That's why Todd spent so much time with Dennis,to eventually get his soul.