This Commander relies on the help of older sets such as Conspiracy that focused on multiplayer environments, such as Kazuul, Tyrant of the Cliffs and Fumiko Lowblood
There is no main phase before the additional combat phase
In most cases, the controller of the attacking creature will still become the monarch as it is likely their turn.
Others can boost your attacks
Mew ex has two moves the humble 20-damage Psyshot which costs one Psychic-type energy, but another, far more threatening attack called Genome Hacking, which costs three of any type of energy, and allows you to choose any of the attacks from your opponent's active Pokemon to use yourself, seemingly with no consequences
If an opposing Active Pokmon has energy attached to it and is ready to attack, a Repel gets rid of it, and the opponent may not have another Pokmon with energy attached yet