Evolution: Start with Warship

Our MC reincarnated into different world with tens of thousands of races, where there was not land to live, 200 years ago water level started to raise and after 150 years all the land the world submerged in the water. so the people started building boats 50 years ago and started living on them. As the water started to raise, the world itself started to undergo changes, first the size started to go and after 200 years the world's size was nearly 10,000 times more than Earth and continue to raise as of now. Secondly an unknown energy called AURA started to fill the world and all the living beings started going mutation. Thirdly all the beasts and plants gone to undergo mutation towards amphibious, and all the humanoid living beings undergo mutation very slowly and among them human beings where the beings that had least mutations almost negligible. Now after 200 years our MC comes to this world, lets see what changes he brings to this world.