Confused...

So, this is a secluded island which trapped the aboriginal people (still no idea why).
And the lord and his descendant who ruled this island know about outside world and only by his permission that outside people can come in.

For hundreds of years, this island been closed off from outside and remind primitive because the lord want to keep them like that, to control maybe, that's why outside technology or anything seems too advanced are not allowed to be brought into the island.

Outside people seems being coming and going out of this island by the permission of the lord since long ago. They are mostly brought in by the lord to act as an observers of the state a Kannagi currently in and report it to the lord.

However, Kanoe and Letty feels empathy to the Kannagi and so they secretly bring in the technology from outside to research whats going on in this island.

Letty has taken several samples of the black sea water inside a lab tube/bacto and secretly send them out of the island to her colleague to check the content.

Letty want to find out how to counter the black sea to save Kannagis and the island people.
But based on the lab test, the water is just simple sea water.

So whatever happens related to the black sea that harm or take possession on people are spiritual/paranormal.

Kanoe think just him and Letty in the island won't be enough to deal with this so he invited his friend there to help.

People of the island has been brainwashed since they are born. And it was more intense on the Kannagi it seems.

From what it seems, Alto is probably born between a man possessed by a black sea creature and the woman from this island.

The woman who married the current lord is also being possessed by a black sea creature, and yes the lord aware of that. They trying to birth a special baby like Alto. But I don't know what the reason yet.

All black sea creatures seems to aware of what Alto existence is and his purpose.

Thanks love