Are they made when you ETB and attack
Withengar even has an ability that lends it to be used in multiplayer formats like Commander, as when another player loses the game, thirteen +1/+1 counters are put on the Demon
You can do it, but it isnt easy
There are two possible invitations players could obtain: a regular 'Day One' invite, and a 'Day Two' invite, which allowed players to acquire a 'Day One' bye and automatically enter the second Swiss tournament
Like many mythics in the set, this wont be opened as much as youd hope, so good luck opening your packs
Fog (and Friends) The classic option to prevent all combat damage is Fog, which has interestingly seen several functional reprints that were color-shifted in Ethereal Haze and Darkness