Gemi has never contributed to the Pokmon TCG before this
When a Pokmon evolves, it keeps all cards attached to it (Energy cards, Evolution cards, etc.) and keeps any damage it already has, but it cant use the attacks and Abilities of the Pokmon from which it evolved
Necropotence takes the simple equation of "one card = one life" and turns it on its head
In a deck consisting of Lugia EX, Magby, and Zeraora (running on and Energies), you can retreat Magby for free, bring Lugia EX to the forefront, and use Juggler to transfer , , and (from Zeraora) to Lugia EX, and make it attack
Once youre done with your above actions you signal that it is the end of your turn, and play continues clockwise
Forged in the fires of Oath of the Gatewatch expeditions