I take it I will just need to buy the 3.5 Dragonmark book?
Everyone reacts to them with fear at best and hatred at worst, so those with aberrant marks will have a hard life. I'm guessing you're planning on including House Tarkanan in some way?
In the past, there were marks that were far, far more powerful. Halas Tarkanan could create an earthquake mighty enough to destroy a city. The Lady of the Plague could lay a curse on a city that has lasted over a thousand years. The Drambreaker could drive you mad with a glance. Essentially, in the past you had aberrant marks with power equal to or greater than Siberys Dragonmarks... Khyber Marks if you will.
From a story perspective, it has been suggested that marks with this level of power are begining to emerge again. However, rules have always been vague. Dragonmarked included rules for a few more powerful marks, but nothing on the level of Tarkanan's mark. Essentially, that's something that's intended as a plot device. I'll note also that the Aberrants of the War of the Mark had dragonshard focus items just like the modern houses; an example of this is the Delrium Stone of the Dreambreaker (as seen in the adventure of the same name), which allows him a wide range of at-will abilities.
The 4E books include a handful of feats for Aberrant Marks, but like the other 4E dragonmark feats, these are power modifiers as opposed to powers. So what are the powers of the marks? There's a few ways to handle this.
Class Powers. One of the things I advise for 4E Dragonmarks - Aberrant or otherwise - is to consider them the source of class abilities. For example, an Infernal Warlock could simply be deriving his powers from his Aberrant Mark as opposed to a pact with an infernal entity. The effect is the same - he drains people's life-force, flings fire, etc - but the explanation is that these are the powers of his mark. It's starting small, but by the time he reaches epic tier he's rivalling Tarkanan. In this case, cosmetically I would have the mark physically grow with the character's level.
Rituals. Provided you could find rituals that were suitable - or make up new ones - you could have an aberrant mark grant access to rituals. This is likely how I'd handle something like Halas Tarkanan's destroy-a-city power. In combat, he could cause localized disasters... to bring the city down, he might have to build up power for ten minutes.
Spellscars. You could certainly use the 4E FR Spellscar system as the basis for mark powers.
NPCs are Wild. NPCs can do whatever you want them to do - so when dealing with Aberrant PCs, decide what you want them to do and let them go crazy.
Tied to that last point, in THEORY, the central difference between aberrant marks and "true" dragonmarks is that pure marks are constructive while aberrant marks are destructive. This is a broad assertion that doesn't always hold true; a few of the "positive" marks have destructive applications. But overall pure marks are things like healing, making, moving, warding... while aberrant marks are coercion, madness, destruction, etc. Aberrant marks may have positive effects with a negative side; for example, the 4E Tarkanan NPC has a teleportation ability, but it functions like Otherwind Stride in that it harms everyone around the teleporter's space; likewise, The Son of Khyber has a character whose mark grants him the power of regeneration, but when he regenerates, he regrows body parts of different creatures (like an ongoing, random reincarnation). So aberrant marks are either dangerous or disturbing... something likely to frighten people. The flavor is also that many aberrant marks have a negative effect on the bearer - either physical (Filleon's wasted arm in The Son of Khyber) or mental. This is something that could be reflected with a fumble effect - the mark does something bad to the user if he rolls a one.
I don't know if that's at all useful, but there you go. If you haven't read it, The Son of Khyber is all about House Tarkanan, and introduces an assortment of aberrant characters.
I was more wondering if there was an actual limit to the sort of power they can pick up. I picked aberrant marks because they felt like something that could easily gel together a 1-30 theme. House Tarkanan would of course not fail to notice these people and want to "aid" them.
Edit: I've also never been worried about letting NPCs do whatever they feel like. It was more about what kind of powers aberrant marked doods should have as a major threat. This isn't really described anywhere except in the distant past.
It was more about what kind of powers aberrant marked doods should have as a major threat. This isn't really described anywhere except in the distant past.
That's because in the present day, aberrant marks don't have the kind of power that they had in the past. The returning power of aberrant marks is a theme DMs can choose to explore, but by default there aren't people in the present day with the power of Halas Tarkanan or the Lady of the Plague. The one canon exception to this rule is the Son of Khyber, who is intentionally left blank so you can decide what he does. One possibility is presented in my novel...
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In The Son of Khyber, he has the power to absorb spirits. This includes the ability to kill people by literally sucking the life out of them, but if he absorbs a powerful spirit - such as an angel or rakshasa - he also gains a measure of that spirit's power. This measures as "destructive" as opposed to "defensive" because it is an aggressive act that kills mortal creatures.
*That he unwillingly or willingly uses for his own benefit: Haven't decided yet.
I'd color the weather-control guy's storms to be freak-weather. Like, flaming hail, or torrential downpours of blood. Or frogs. You know, something weather-related, but more disturbing than regular snow or lightning. This would help differentiate him from a Lyrandar heir with the Mark of Storm.
I think overall he is pretty destructive, given the whole snap freezing quality of his mark and that he literally destroys everything living around him (that isn't a cold type monster anyway).
He's there as more of a moral dilemma for the players. He's not in any manner actively evil or destructive - his presence just causes things to die due to his utter lack of control over his mark. It's entirely up to them how to solve this and there are numerous options available. I will be curious to see if they just murder him outright though.
Oh and expect the worst of your players Aegeri, if there is an option to kill they'll probably take it
.For true marks, their power lies in the useful, constructive applications, as said. I allow the mark based rituals of 10 minutes or less casting time to be done without components by spending a healing surge. Ones over 10 minutes can be done once a day by spending 2 healing surges, without components. (This also explains why there is a non-mark version of each ritual effect, they developed them to avoid being tired out by their job, so to speak) For NPCs, I simply give them Con Mod+1 healing surges to power Rituals.
Aberrant Marks, however, can learn related rituals to their marks (I have my own list of what rituals go with each of the three versions in case a player decides to manifest one, i'd make your own based upon your story needs), and perform them in much the same way, but they use other peoples' healing surges to do it. What does that mean with a world where only a chosen few people actually have healing surges? Well, they die as the Aberrant Mark rips out their soul to power the ritual.
Also, as pointed out, the powers the NPC has can be flavored to come form their mark rather than their class or template. It works quite well. The cursed Guardian Template (DMG2, pg 126) is really good for a Mark of Madness, for example.
I'm going to use a plot device aberrant character that is able to permanently remove true dragonmarks.
That ! That is neat ! I'd go further with it.
Lock him up in Dreadhold. This Aberrant is too dangerous to let loose, and yet, he has other powers that prevent any Dragonmarked House to kill him. Maybe after 'erasing' a mark, he has better knowledge of the Prophecy, maybe he can emulate the mark's power (like X-men Rogue), maybe he also has the power to give out dragonmarks true and aberrant, maybe his imprisonment was plotted by Vol who want to use him as a component in a ritual that would reactivate her mark (but the other components aren't assembled and the ritual needs further studying)
Tarkanan would probably want to prison break him, but what else could be set free at the same time?
Rekko