You're human. [ it's a small sentence--a simple one--but it gets across at least part of something he needs to say--to remind himself, to remind waver. ] Compared to me, you'll live maybe one hundredth the length of time that I will.
So it's hard, isn't it? To see the future as something that can easily change; because you have so little time.

[ humans live short, brittle, fantastic lives and Vash wishes he understood what it felt like, so he could understand people like waver better. So he could understand that helpless feeling that he has in his heart--that feeling that nothing can change, because there's just no time for it. ]

You don't need to become the same as the gun in your hand. Just because your future is short.
But. There are ways of utterly defeating your enemy without taking their lives, that's all I'm trying to get across.

The enemy you fought--you stole his life, his future. And maybe, if he had his way, he would have stolen yours as well. So I understand why you decided the only future necessary would be one were he died.

But it doesn't have to be that way for every enemy you face, Waver.
You can choose mercy. Next time.