The Entire island is the remanants of an attempt at Resurrecting a living person
- The entire island is populated by clones of extinct animals, or their descendents, who were created in an attempt to perfect either cloning or resurrection for the purpose of bringing Miina Isurugi back to life. But it didn't work. So they put a "Grave Marker" there as a tribute to her and abandoned it. ages ago.
They traveled forward in time.
- Miina's grandfather created the island and all the animals as a gift/memorial to his lost granddaughter. The island is man-made and created there on the last known location of the plane that was carrying her. All the animals were animals that she had drawn in the past.
- Pretty much confirmed in chapter 166.
- And even more hints of this in chapter 169, when they find a car of a model not known to them
- From the looks of it, Chapter 182 seems to have confirmed it.
- It's the future, but its the original timeline.
- Or... they're actually clones of themselves, at least based on the work Miina's grandfather and Akira's mom were doing.
- They can't be clones - cloning people, keeping them in coma till they reach the right age and then wake them on the island you've prepared is one thing. However they have the memories from Guam AND the flight itself, even if those are fabricated they still have their stuff - phones, laptops and so on which would be antics those 60 (I guess more than 100) years in the future with software and data from the "present" time. And finally - who would have done that? Miina's grandfather and Akira's mom went very far to make sure the project was led by someone who cared after they passed away - would a person like this clone everyone and put the clones on the island to watch them die horrible deaths?.
Yarai's father helped create the research facility
- According to Kurusu-sensei, Yarai's father works at a foreign corporation. We know that the research facility was funded by several different corporations.
Yarai wants to be a doctor.
- Otherwise how would he know so much?
Hades is a failed Akira clone.
- There, I said it.