The Summoner: a 5e Class Where You Literally Play Magic the GatheringWhile Everyone Else Plays D&D

UPDATE

Obiously, the math is off, as I indicated originally. I've not gotten around to testing things at higher levels, but we're all grownups here and can adjust as it comes up in our campaigns. 

For now, I think I'll work with replacing all attack/toughness calculations with the following: 

Power or Toughness = Power or Toughness x Proficiency. 

Maybe that's a bit weak, but we'll have to see.

Destroy a creature: probably this effect should only work if the creature has <= hp than you currently do; otherwise, it does damage = your current hp.

Toughness variant: instead of being killed when they take so much damage over the course of a round, summoned creatures have an AC = 10 + proficiency bonus + toughness. If their AC is hit, they are killed. If they need to make saving throws, their bonus is their toughness.

RESUME ORIGINAL POST

This class lets you actually play Magic the Gathering within a 5E D&D game.

Really, the conversion is so simple I don't know why I haven't written it up ages ago.

The writeup assumes you already know how to play M:tG, have cards, etc.

Overview

It lets you play Magic within D&D. In a fight, you're initially at great risk, and you may not have anything immediately useful to do (such is the luck of the draw). However, with a fast-playing deck and some allies relieving pressure on you, you can lay down some destruction. And there's nothing saying you have to limit your summoned creatures to combat functions.

Class: the Summoner

Hit Points, Proficiencies, and Equipment: as wizard, except up to 5 components pouches instead of 1

Special Components: you start with up to 5 pouches. Each contains a handful of a different land:

• a handful of water (blue mana)
• a handful of ash (red mana)
• a handful of loam (green mana)
• a handful of pale grass (white mana)
• a handful of black moss (black mana)

You must either have these components on your person or be in a suitable region (in plains, in swamp, etc.) in order to tap the related color of mana.

Spellcasting

Cantrips: Summoning Circle, Summoning.

You do not use the 5e spell list. Your only magical abilities are those in your Magic deck, plus the ability to summon and make a summoning circle. Intelligence is your spellcasting ability should you need to specify one.

Summoning Circle: if you do not move on your turn, you can use your action to drop a half-handful of your special component(s) onto the ground in a rough circle around you. It does NOT have to be unbroken line but only a circle clearly identifiable as a circle. Now you have a summoning circle.

• While summoning within the circle (i.e., not during the turn in which you are creating it), the circle acts as a physical barrier
• Any damage done to you is instead done to the 'walls' of the circle. 
• *The circle resists all damage (i.e., halves damage taken)
• You share hp with the circle
• When the circle reaches 0 hp, it is destroyed, along with the component material used to create it, and you follow the 'being at 0 hp' rules as well
• If you exit the circle, it is destroyed, but the component material remains and may be gathered up for reuse (which is a bit harder with water)
• While in the summoning circle, you can control anything you have summoned, as in normal M:tG
• The circle remains as long as you concentrate on it

Summoning: when you start summoning things, you are playing Magic!

• Summoning takes an action and does not require concentration, only consciousness (i.e., you can get hit and still be summoning)
• Summoning only requires material components
• When you begin summoning, draw your hand as usual for M:tG
• Take your turn as normal in both D&D and M:tG 
• You can play lands, tap mana, and play the cards you have the mana for
• You can move, talk, do whatever
• Your summoned creatures have 30' movement by default (GM may adjudicate different rates for different creatures)
• You can only see what you can see and sense what you can sense, but you can control your summoned monsters over any distance so long as you remain conscious and have the components to draw the proper mana from
• Even when it's not your turn, you may move any of your untapped summoned creatures to block attacks (per standard M:tG)
• Blocked attacks do no damage to you or your summoning circle but may kill the blocking creature
• *When you attack with a summoned creature (or any other card), it does damage equal to its (attack x your proficiency bonus) + your summoner level
• There is no attack roll. Remember: you are playing Magic. 
• *When a summoned creature of yours is attacked, its defense equal to defense x your proficiency bonus
• Your creatures and your summoning circle have no AC; every attack automatically hits. Remember: you are playing Magic. 
• While conscious and NOT in a summoning circle, you can control creatures having a summed mana cost no greater than your summoner level (e.g., at level 1, I can control a creature that costs 1 mana, at level 2, I can control one that costs 2 or two creatures that each cost 1).
• Summoned creatures have names and personalities and goals. If they are freed from your control, they will pursue these goals with abandon, whatever they are. When they are killed, they return to wherever you summoned them from, to be summoned again. You might want to stay on good terms with your creatures so they don't try to kill you as soon as you break your circle
• A summoned creature is killed when it suffers damage = its toughness x your prof bonus, plus your summoner level) over the course of a round.
• Otherwise, GM adjudicates card effects using the above as guidelines

Example Cards (2015 Core)

• Caustic Tar: 4, 2 black; enchantment — aura; enchant land; enchanted land has "tap: Target player loses 3 life". ADJUDICATION: target creature loses (3 x proficiency) + summoner level life. 
• Invisibility: 2 blue; enchantment — aura; enchant creature; enchanted creature can't be blocked except by walls. ADJUDICATION: creature is invisible; easy.
• Mind Sculpt: 1, 1 blue; sorcery; target opponent puts the top seven cards of his or her library into his or her graveyard. ADJUDICATION: target loses its action. 
• Torch Fiend: 1, 1 red; creature — devil; 1 red, sacrifice torch fiend: destroy target artifact. Adjudication: the fiend moves up to a creature and blows up an item.
• Venom Sliver: 1, 1 green; creature — sliver; sliver creatures you control have deathtouch. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.) Adjudication: SEEMS LEGIT.
• Flesh to Dust: 3, 2 black; instant; destroy target creature. It can't be regenerated. Adjudication: only if you have more hp right now; otherwise, deal damage = your current hp.
• Soulmender: 1 white; creature — human cleric; tap: you gain 1 life. Adjudication: you get 1 + proficiency bonus + summoner level temp hp.

* May need scaling adjustments. This is not even back of the napkin calculation. Seems fine at apprentice levels to me. If it's too powerful, I see easy adjustments.