A new MTG mechanic in Doctor Who decks shakes up Commander format

Wizards of the Coast dropped new information about the upcoming Commander Doctor Who set today, highlighting a new Magic: The Gathering mechanic that allows for two commanders on the battlefield from one player at the same time. 

Tapping into the flavor of Doctor Who, WotC has created a new mechanic that allows players to play multiple commanders at the same time. Throughout the history of the television show, a Doctor always travels with a companion. The new MTG mechanic Doctor’s Companion lets players have two commanders in their deck if one is a Doctor.