Lets just get to it
Its like hes holding up a big sign that says, "Pretend I'm whoever you need me to be!" This makes it way easier to flood the board with your powerful Floodborn characters and gives you a huge economic advantage without all the waiting and wishing
Adds mana, gains life, draws cards, makes your creatures bigger, and usually costs around 2-4 mana
His minus tucks any nonland permanent into its owners library
It can go dead in the late game, but its much less likely to than something like Spell Pierce because, with four players, you regularly get turns with very high storm counts, especially when someones trying to win
Although no official pre-orders have gone up for Archazias Island yet, the previous set, Azurite Sea , may be a good indication of how it will work