Also, I think this shows the parallels between J and Makoto. J's love for W eventually turned into hate, which made him destroy his master after he rejected him. But in Makotos case, his hate turned into love (or moreso obsession) and he destroyed J by promising to love him by saying his name. In the manga both Hate and Love were distinctly mentioned as being things that could shatter a demon.
Did J kill W? I haven’t read the second vol in a minute. I just thought he killed himself
People assume he did but it’s kinda more complicated. Essentially it’s a cycle. A demon becomes incredibly powerful that now they can’t die, they find a young weaker demon (or human) that has some sort of intense desire (could be a desire to survive or a desire for power but it needs to be strong), powerful demon decides to take the younger/weaker demon and groom him into a perfect demon lord, younger demon becomes more powerful and more obsessed/in love with the older/more powerful demon, eventually younger demon surpasses older demon, older demon says the name of the younger demon allowing them to die.
Which makes me wonder if Wald was the dart of this cycle or continuing it. I would kill for a younger Wald-centric chapter.
So in the end J says that its a pact before disappearing when Mako promised to say his name for eternity. I wonder if its a real pact just like the one Mako has with D and S. For Mako to get the end to his loneliness, he has to break the pact by not calling Jonathan anymore.
But because of Mako's obsession with J, he will not and will continue to suffer for a long time and disappear the hard and long way.
What a beautiful way to show how deep inside Makoto is still under J and was only fooling himself the entire time.