Between fallen angels and humans, who is responsible for sin?

For whose sin?

tiggerS

I wish to further my position.
Yeah. So when on 1 John 5:16-17, John mentions "I refer to those whose sin does not lead to death.", he is talking about Spiritual Death, because the context of the verse has been set on spiritual.

On Catholic Doctrine, perhaps you can translate this to,
"Pray to those that commit venial sins",
"But if someone sins mortally, you must talk to him about it".

Mortal sins send to hell, which is the second death.
Venial sins can lead someone to mortal sins and are evil, but don't send to hell by themselves.

Satan and all that decided to follow him on the angels side, and Adam and Eve on the human side.
Both creatures are responsible for their own sins.