In the book version the ending is very good, you can feel the pain, suffering and all the people and friends gets to know the good side/sacrifice of the main lead but here in drama it all went very fast and you can't feel the same kind of emotional connection you feel in the start or mid of the story. They should make a special episode to make it clearer. But still it's okay.

Rewatch value 10/10
They should make a special episode to give clarity on what happens to devil realm, what happens to the immortals who kind of died and how he sacrificed his life to save everyone. In book it's clearly written but here . ?