To summarize more into Emmit's death, we have to look at the video posted. (Note that it is age restricted for some)
For those who can not see it, here are the transcripts
Emmit claims that he wanted to kill Devin because he believes no one should mess with the fourth wall. He also claims that he killed all those people for good reasons.
When it comes to his death, he said that I was likely Beepo and Euan that did it.
Note that everything he says should be taken with a grain of salt.