Use cards like Mahadi, Emporium Master to generate a huge amount of treasure tokens after Rakdos triggers his ability, then use them to cast the rest of your Demons
To hit Twilight Sparkle's win condition, you'll need to search for a couple of other Ponies
The best way to achieve this is with a well-constructed mana curve
While she costs only three mana one red, one green, and one of any color because her saga sides final effect generates 10 mana spread evenly across all five of Magics colors, her color identity is also all five
The card specifies what you do with the land, sometimes very plainly like the transformed Rona, Rona, Tolarian Obliterator
It works well, and it creates a new archetype that tries to cast it and then turn it into a powerful creature as soon as possible