I've always liked the idea that not all tieflings need share the exact same qualities. After all, there are many types of devils, and it stands to reasons that some tieflings (or tiefling families) might display other benefits from their pacts. I allow this sort of cosmetic adjustment in my games despite the "official" stance being that they all have horns and tails, and I've specifically stated that in my Eberron games players can opt to display the cat-like features of a rakshasa instead.
If a player bothered to play a tiefling, I'd probably allow some sort of feat tree to emphasize that...which is what The Broken Mirrors is all about.
Some families made a deal with Levistus, and in doing so can inflict misfortune upon the world. Any tiefling can opt to belong to the broken mirrors by picking up the Mantle of Misfortune feat, which is a tiefling bloodline feat that gives you an encounter feat power of the same name, as well as a bonus to Insight and Perception. The actual mantle of misfortune power is pretty potent, imposing an automatic attack penalty to all enemies within a pretty hefty range. To top it off, if they miss you get to slide them.
Like all bloodline feats, Mantle of Misfortune is a gateway feat to the few others included in the article. There are two that let you mark creatures or get an attack bonus against creatures that you slide due to mantle of misfortune, which is pretty sweet and gives tiefling defenders a nice edge. The last one is kind of wonky in that you get to roll multiple Insight checks against creatures affected by mantle of misfortune, which I guess gives it some interesting social encounter potential. >_>
The article also adds a paragon path called broken mirror, which is only open to tieflings with the Mantle of Misfortune feat. The features let you use mantle of misfortune twice, slide or prone creatures when you burn an action point (automatically), and eventually let you add your Charisma mod to mantle of misfortune damage.
The level 11 attack is interesting in that its an encounter kicker that you trigger with a minor action, and stacks on an attack you make. It adds a nice damage bonus and also prones a target. The level 12 utility lets you generate an area of effect that imposes attack and defense penalties in addition to sliding targets that stop in the area. It can be sustained, which gives you a really nice debuffing power. Finally, the level 20 attack is similar to the level 11 power in that you trigger it and stack it on another attack. It deals more damage, prones, and you can slide it whenever it misses no matter where it is.
Not a bad article despite its incredibly short length. I'm a massive fan of tieflings, and want to see more of these articles expand on specific devil pacts. My next campaign takes place in the ruins of Bael Turath, and I'm going to "encourage" my players to give them a shot. At least the article provides me with an interesting way to implement such specialties. ^_^