For a mill deck to be viable in Commander, it has to target all opponents and turn mill into damage or some other benefit, and you should aim for big/infinite combos when possible
Battles can be cast during your main phase if the stack is empty, just like creatures, sorceries, and other non-instant spells
If you believe you have an Exhibition (Bracket 1) or Core (Bracket 2) deck using one of these cards (for example, your deck commanded by At Upgraded (Bracket 3), it means it counts toward one of your three Game Changers
This Emerald card allows any character with Shift to be played on it as if this character had any name
Today, you will hear a lot about mass removal
Where this card can become really spicy is with Zada, Hedron Grinder, since Zada creates copies of the spell, all your creatures will get the +X/+0, first strike and trample