Here’s an interesting and a seemingly (and probably actually) bad card.
This is going to be casual at best. Well, maybe there will be something more interesting in the future, which brings this to a new level, but until then its going to be more about simple fun.
What to do with that? Supposing you open a mythic while drafting and this is it, what would you make of it? Probably not much. I hope there are ways to abuse this in Magic Origins so no-one has to go through that, but this is also clearly one of those “build-around” cards you see in each set.
One classic way to use this would be to give it to your opponent. There’s at least [scryfall]Daring Thief[/scryfall] and [scryfall]Shifting Loyalties[/scryfall] that can do exactly that. However, you can’t really rely on your opponents playing enchantments. Neither can you rely on a card as expensive as the latter or as awkward to use as the former.
Of course destroying the thing before you lose the game to it is fine as well. Preferably you’d like to do this as a side-effect of something else. How about [scryfall]Ugin’s Construct[/scryfall]? It makes you sacrifice a permanent with a color… like this enchantment.
Then you could always recur it. There’s always plenty of ways of doing that. The current standard has [scryfall]Jace, the Living Guildpact[/scryfall], [scryfall]Retraction Helix[/scryfall] (note that it can also be used to tap [scryfall]Daring Thief[/scryfall] if you can’t attack with it), [scryfall]Rite of Undoing[/scryfall], [scryfall]Silumgar’s Command[/scryfall], [scryfall]Void Snare[/scryfall] and [scryfall]Void Squall[/scryfall].
So, lets maybe try this in a GTA shell?
4 Daring Thief
4 Pain Seer
2 King Macar, the Gold-Cursed
1 Tasigur, the Golden Fang
4 Springleaf Drum
4 Ashiok, Nightmare Weaver
3 Demonic Pact
4 Triton Tactics
4 Rite of Undoing
4 Hero’s Downfall
2 Jace, the Living Guildpact
4 Temple of Deceit
4 Dismal Backwater
4 Polluted Delta
From the flavor point of view the Demonic Pact captures the feeling of Liliana’s Pact. She gains power through it but has to negate it in order to survive.