Lin Yun had always thought he wouldn't dare to kill anyone, which is why he still hesitated when he thought that Wang Wanqiu couldn't be left alive.
However, it was after the battle with Baili Shouce that he realized he wanted more than just to hack someone into pieces; he wished for even more blood to be spilt.
Am I a demon?
Before he killed Baili Shouce, he was psyching himself up, telling himself to be ruthless and show no mercy.
Yet when the time came to act, he pulverized the man with a single move and still felt unsatisfied.
It was a bit frightening.
"I should avoid killing people without good reason in the future. I've got this feeling that if I keep on killing like this, something terrible will happen."
This was Lin Yun's intuition, without rationale. In short, he should keep his hands off in the future unless necessary, and if he must take action, then he should use fire instead. Maybe the absence of blood would dampen his excitement.