Once you join that assassin organization, it means your life no longer belongs to yourself, but to the organization, to your superiors. If your superior wants you dead, you have to die. If you dare disobey orders, you'll be seen as betraying the organization and will be hunted down by them, never to the death.
In this world, there are many things ordinary people can't understand. Just like the online world we can see only takes up a tiny fraction; in the dark there's a much bigger net, like an iceberg, with only a small part above the surface and far more hidden in the dark depths of the sea.
What kind of person would willingly become a killer roaming in the dark? Willingly put his life in someone else's hands?
Those cold-blooded, ruthless killers, their life experiences are probably full of darkness and complexity, things ordinary people can't know and can hardly even imagine.
