Magic Origins: new mechanics

Magic Origins set is on the way, hence it is high time to introduce new mechanics:

• Renown X 1 - whenever this creature deals combat damage to a player, if this creature is not renowned, put X +1/+1 counter on it and it becomes renowned until it leaves the battlefield. The ability will neither trigger if the creature deals combat damage to a Planeswalker nor if renowned creature loses its all +1/+1 counters.
• Spell mastery - if there are two or more instant or sorcery cards in your graveyard your spell will be pumped and you get a special effect. Don't count the resolving spell itself. It's still on the stack at that point, not in your graveyard.
• Menace - is a new keyword for an old ability. A creature with menace can't be blocked except by two or more creatures.
• Double-faced planeswalkers - if a creature meets a specific condition it will be transformed into Planeswalker.