So, without further ado...enjoy!
Color: Blue creature
Location: In the Ocean (underwater).
Action: A huge ocean monster that is comprised entirely of hundreds of fantastical squids. He is 15'-20' feet tall, roughly humanoid in shape, though he could have multiple limbs and should be frightening in appearance.
Focus: The monster made up of squids.
Mood: A monster rises up from the deep!
Color: Black creature
Location: A moonlit night under moss-draped trees.
Action: It is a moonlit night and you have just encountered your death. It is in the form of young girl (12-15 years old) with a smooth porcelain face and just the hint of a smile. Rivulets of blood trickle from the outside corners of her eyes.
She is an assassin and could have anything from silver needles to a butcher's cleaver as her weapon of choice—up to you. Her costuming could be a strange Victorian style suit-dress—up to you.
Focus: The young killer.
Mood: Creepy, lethal.
Color: Red Creature
Location: open field; perhaps a battlefield
Action: A goblin is bending down to dig a hole with a spade he's holding in one hand. In his other hand he has a round bomb with a lit fuse. He is so focused on digging that he hasn't noticed that the lit fuse has ignited another fuse that is arching over his shoulder from his backpack full of bombs.
Focus: the goblin
Mood: uh oh
Ob Nixilis, Unshackled
Color: Black legendary creature
Location: Guul Draz, Zendikar in a basalt temple.
Action: Show the demon Ob Nixilis. He is in his 2.0 state which means he is more powerful and has wings! And he no longer has the hedron shaped cross in his forehead. He looks at us like a starving tiger would look at a helpless fawn.
Focus: Ob Nixilis
Mood: Epic. The badass of all demons.
Color: White spell
Location: On a battlefield.
Action: Standing with her sword at the ready is a female, African-skinned paladin warrior. Hovering over her is a spirit of an ancestor, a male warrior who is dressed in ceremonial armor and has a shield looking over her with protective care.
Maybe fallen foes lie all around the paladin.
Focus: The paladin and her protective spirit.
Mood: Protection from beyond.
Yisan, the Wanderer Bard
Color: Green legendary creature
Location: In a field by a forest.
Action: Show a badass human ranger-type with a sword and leather armor. In his other hand he is holding a lyre or some type of stringed instrument.
Maybe there's a huge mammoth or wurm behind him, filling the frame.
This guy is a unique character in Magic, so feel free to make him distinct in his costuming starting at a base fantasy ranger/bard and elaborating from there.
Focus: The warrior musician.
Mood: "I shall compose a verse for your funeral."