User blog comment:IamJakuhoRaikoben/Chapter 393: Silver Memories, Review./@comment-1359322-20140717104322/@comment-1359322-20140717114355

@anon, there's no way anyone in FT is going to that, how would they even meet much less talk to Gray if they kill Silver, the one that did it will be plunged with guilt and Gray himself would find it hard to meet that person.

Also kindness has many forms like Silver shown, he acted as a villain to help Gray overcome his issues. In this case, Gray killing Silver is also a form of kindness in its way, he as a son is going to help Silver become free of all his issues in the living world. Being alive and being kept alive are two very different things. Gray is alive but Silver is being kept alive. Silver was kept alive by Keith and Silver's own hatred towards Demons for killing his son and wife. Gray can be the one to end that curse placed on Silver.

As Keith mentioned, his curse has something to do with Karma, Silver's fate became his karma and Gray should've been the one to sever that karma and release Silver from that karma but he couldn't, which was pitiful.