Starting June 1st for paper Magic players and June 4th for Magic Arena and Magic Online players, how companions work is changing

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All the Legendary Pokmon are pretty powerful, but in terms of pure raw stats, Arceus is the strongest
C Slate Street Ruffian An interesting, readily available cipher target that forces the opponent to either get hit and suffer the encoded spell, or block and (hopefully) trade and lose a card
It's in all the preconstructed decks