So M15 boosters include these cards with some background on the First Five.
Ajani Goldmane
Ajani Goldmane is a Planeswalker who wields whit magic. His specialty is magic that purifies the body and soul: spells that heal and strengthen his allies and evoke their inner spiritual essence.
Jace Beleren
The Planeswalker Jace Beleren wields mental magic aligned with the blue mana: spells of illusion, deception, and mind reading. With nearly unlimited access to knowledge comes the temptation of power, and Jace is tested every waking moment.
Liliana Vess
The Planeswalker Liliana Vess is a necromancer who wields black magic. Her foul spells corrupt the living and reanimate the dead. In her mind, everyone is self-centered and ruthless---she's just better at getting what she wants.
Chandra Nalaar
Chandra Nalaar is a Planeswalker alighted with red mana. Her specialty is pyromancy: spells of fire, fire, and more fire. Impulsive, passionate, and short-tempered, Chandra is always ready to unleash her fiery arsenal and reduce any obstacles to ash.
Garruk Wildspeaker
The Planeswalker Garruk Wildspeaker is a predator whose hunting ground is the entire Multiverse. Cursed by the necromancer Liliana Vess and corrupted by black mana, he now seeks out the most dangerous game: other Planeswalkers.
I am actually rather disappointed by this text--particularly Chandra's which seems to simply miss the mark completely with her character.
Also, I think referring to them by color ["aligned with x mana"], is lazy....Liliana is a necromancer--that has meaning. It is a school of magic not a color of mana & I think Liliana's profile is likely the best.
Garruk's profile moves the story into the next block by focusing on Liliana's curse, but the other cards do not really seen to add anything & feel rushed. Magic could easily do a lot better than this--actually, just about any player I know could craft more interesting & informative Planeswalker profiles in three sentences.