Paladin
Resides: Plains
Life: 12
Preferred Magic: White, Blue
Card Profile: Since his deck is loaded with anti-black cards, you'll want to avoid using a black deck against him. Try using a two-colored or even a tricolored deck so that his color-specific cards won't hurt as much.

Priestess
Resides: Plains
Life: 6
Preferred Magic: White
Card Profile: The Priestess takes the stance that the best offense is a strong defense, which she stacks considerably in her favor with Walls and life-gaining effects. Use something that will protect you from her 1/1 creatures until you can build up your mana to summon a creature that can get past her Walls.

Prismat - Green Dragon
Resides: Forests, Mountains, Plains
Life: 18
Preferred Magic: Red, White, Green
Card Profile: Surprisingly, this deck has almost no creatures except Onulets. Prismat prefers to fight you with spells and effects that hurt everyone, and then use his life-gaining cards to help himself. He needs a lot of mana to use any of his mass damage spells, so any land destruction cards will hurt him. You also may want to try Wrath of Gods and Energy Flux to slow him down.

Queltosh - Red Djinn
Resides: Islands, Mountains, Plains
Life: 13
Preferred Magic: Blue, White, Red
Card Profile: Queltosh has a ton of spells but only one of each. His strategy will depend more on what cards he pulls up than anything else. Realize that once you've taken care of a particular threat he has dealt, you'll never see it again, as there are no repeats in his deck. Focus on land destruction as he's got a tricolored deck.

Saltrem Tor - Green Djinn
Resides: Forests, Islands, Mountains
Life: 13
Preferred Magic: Red, Green, Blue
Card Profile: Because of the extra Forests and Birds of Paradise in his deck, Saltrem Tor is less vulnerable to land destruction cards. Most of his spells have a low casting cost, so he may hit you quickly. Try your hand at mass damage spells, flying creatures, and midsized beasties to get past his defenses.

Sea Drake
Resides: Islands
Life: 12
Preferred Magic: Blue
Card Profile: The Sea Drake uses large aquatic creatures and a Phantasmal Terrain to turn one of your lands into an Island, letting the Drakes walk all over you. Although his Jump spell will help protect him from flying creatures, an aerial offensive is still a good start. And considering the high cost of most of his creatures, a fast deck may be the way to go.

Sedge Beast
Resides: Mountains, Swamps
Life: 10
Preferred Magic: Red, Black
Card Profile: The Sedge Beast prefers to focus on land destruction with cards like Strip Mines, Fissures, and Stone Rains. You'll need either a lot of land in your deck or non-land mana sources, as well as creatures with a toughness greater than two.

Seer
Resides: Islands
Life: 4
Preferred Magic: Blue
Card Profile: The Seer relies on several killer combinations in her deck like Time Elemental with Unstable Mutation. But because of her low life, she rarely lasts long enough to use any of these. Any reasonably fast deck should take her out quickly.

Shapeshifter
Resides: Islands
Life: 16
Preferred Magic: Blue
Card Profile: All her attacking creatures are artifacts, making anti-blue spells almost worthless. Pull out a Circle of Protection: Artifacts as well as any anti-artifact spells you may have. You'll need a fast deck and a few land destruction spells to completely take care of her.

Sorcerer
Resides: Mountains
Life: 6
Preferred Magic: Red
Card Profile: Lots of small creatures and spell pumpers are this foe's theme. But because of his low life, a fast deck with direct damage and point-a-turn enchantments will work well in finishing him off.

Sorceress
Resides: Mountains
Life: 4
Preferred Magic: Red
Card Profile: Like most low life creatures, the Sorceress can't handle a lot of direct damage spells nor, considering her red deck, does she handle Mountainwalking creatures well. With no way to deal with enchantments, a Conversion or Circle of Protection: Red will finish her off, if she lasts that long.

Summoner
Resides: Forests
Life: 11
Preferred Magic: Green, White
Card Profile: Use any color against her but green as she has Circles of Protection: Green. Because of the relatively high casting cost of most of her creatures, a fast deck should deal quite a lot of damage to her before she can pull out the big cards.