So everyone dies of something?

Both they die but the world is recreated and is going to keep on recreating till kiba and the rest of them open paradise

My opinion is that all of them have died... They went to haven, that bloem Maiden made for them. They are living freely without enemies. But she couldn't make them remember what they were coming through and that all of them were friends, but she has feeling that they will meet again.

maybie u know tsume hige & toboe but it didnt say if kiba died

All of them die in the last episodes but later on the come back different for some parts.

pretty much but their reborn i think because the world restarted but this new story discription will be in season 2 and people say kiba is the only 1 who remembers any thing

There is endless debate that will not see an end on whether of not the characters die, of if they find paradise. In the Manga (It came out after the Anime) it ends happily ever after. As for the Anime, it leaves u guessing at every turn. We will never really know what happens unless we ask the original author.