Commander 2016: mechanics

Normally, I would not write a word about Commander 2016 mechanics, but one of them is totally a breakthrough and it is worth mentioning, even if you are not an EDH player consider it as curiosity.

A partner. It is a fresh new rule to the format and it feels very simple and intuitive to me, sliding in elegantly into the existing Commander framework. A player may for the first time have two commanders if each of them has the partner keyword. There are fifteen legendary creatures wirh partner keyword. What does it mean to have two commanders? First of all, both commanders contribute to the deck's color identity, so if one commander is Blue/Black and the other is Red/White, your deck can include cards from these four colors. However, your two commanders are treated individually for all other Commander rules. If either leaves the battlefield, you can return it to the command zone instead. The additional cost of 2 for every time you've cast a commander from the command zone, applies individually. Combat damage dealt by each commander is similarly tracked individually. If either commander can deal 21 or more combat damage to a single player over the course of the game, that player loses.

and other a bit less spectacular new mechanic is:

Undaunted is a new keyword mechanic appearing on rare noncreature spells. Spells with undaunted cost one generic mana less to cast for each opponent in the game. Therefore, they become more expensive to cast as the game overruns and players are eliminated. But even if it is down to two players, you still get a 1 discount.