Mechanics of M15

M15 is the 16th core set and features 269 cards (101 Commons, 80 Uncommons, 53 Rares, 15 Mythic Rares, 20 Basic Land). Consequently, WotC changed the default from 60 uncommons to 80 uncommons for large sets. The magic online release starts on July 28.

The only new (returning) mechanic is convoke, which works by allowing a player to tap creatures to reduce the cost of a given spell. The every creature that is tapped reduces the cost by one mana of the color(s) of the tapped creature.

Furthermore, M15 introduces a few cycles as follow:
- Souls: six 6/6 Avatar cards: Soul of Theros, Soul of Ravnica, Soul of Innistrad, Soul of Shandalar, Soul of Zendikar and Soul of New Phyrexia.
- Paragons: five 2/2 color Lords giving +1/+1 to the color they support - Paragon of New Dawns, Paragon of Gathering Mists, Paragon of Open Graves, Paragon of Fierce Defiance and Paragon of Eternal Wilds
- Painlands: 5 lands producing enemy colored mana - Caves of Koilos, Shivan Reef, Llanowar Wastes, Battlefield Forge and Yavimaya Coast.
- Staves: 5 artifacts allowing its controller to gain one life whenever a spell or land of the appropriate color is played - Staff of the Sun Magus, Staff of the Mind Magus, Staff of the Death Magus, Staff of the Flame Magus and Staff of the Wild Magus.
- Sedge creatures: 5 creatures that get +1/+1 if you control a basic land of the appropriate allied color. They also have an ability in allied color - Dauntless River Marshal, Jorubai Murk Lurker, Nightfire Giant, Kird Chieftain and Sunblade Elf.
- Slivers: Constricting Sliver, Diffusion Sliver, Belligerent Sliver, Leeching Sliver and Venom Sliver.
- Planeswalkers: Ajani Steadfast, Jace, the Living Guildpact, Liliana Vess, Chandra, Pyromaster, Nissa, Worldwaker, and Garruk, Apex Predator.

Next week how to draft m15.