Ok so when Yuzuru learned the truth of being a demigod, he realizes that he and Takumi would end up like their father so he goes to kill himself at the shrine aka burning(but doesn't take Takumi with him for some reason, maybe because he didn't want to see Takumi suffering). But he survives the burns and Yuzuru and Takumi makes up. Then, after settling everything they both go and suicide together. So the ending means that in them to be forever together as spirits who live at the shrine.
There is a better explanation of you scroll down a little more
thx i got it now... i actually read 2 times ╮(￣▽￣)╭ but didn't get it hahahha but now it's clear (▰˘◡˘▰) thx a lott
anyone could please explain me about the ending and how did he get burned