Shadow of the Sea Lord - The Yellow Sign

Freeport isn't your run of the mill fantasy city. It's not even a run of the mill pirate city. A mix of pirates, magic, black powder weapons, ancient relics, demi-human races, and dash of Lovecraftian horror. In Freeport the Yellow Sign (which is technically not a creation of Lovecraft, I know, but is very much within the domain of "Lovecraftian horror") is the sigil of the Cult of the Unspeakable One (no, not Voldemort). The Yellow Sign and the Cults of the Unspeakable One figured prominently in the events of the original Freeport Trilogy and it has been established that the Yellow Sign is an arcane symbol of such power that just looking on it can draw a mind toward madness.

Given the power of the yellow sign it seems appropriate to consider the mechanisms of the Yellow Sign with regards to how it can affect players and NPCs. Thankfully Shadow of the Demon Lord already has some robust rules for madness and insanity, and as such the Yellow Sign merely needs to be fit within those rules.

Warning, spoilers for the Freeport Trilogy and possibly madness will follow.

Any exposure to the Yellow Sign should have the potential to instill madness. In SotDL terms this will obviously be a challenge roll with failure granting one or more points of insanity. I want the Yellow Sign to be something that is always a threat, but not always a dire one. If you know the lore in Freeport the "quality" of the Sign can impact how powerful a given sigil is. The construction of Milton's Folly, with bricks that were each inscribed with the Yellow Sign, helped to act as a conduit and amplifier for the lighthouse's beacon itself. The result was a threat on a truly epic scale that could drive a person mad with a single glance.

To help show the degrees of power in the Yellow Sign I'll be using banes and boons and also modifying the amount of insanity gained on a failed roll. For truly powerful uses of the Sign there may even be insanity gains for successful rolls showing that no mind can withstand the level of otherworldly madness.

Yellow Sign (basic) - This is a basic inscription of the Yellow Sign. It is not poorly carved/drawn nor is it especially well carved/drawn. This is likely not actually yellow in color either (a trait which some ascribe greater potency to). Likewise this inscription is in no way magically endowed or enchanted. Even the most crude rendering of the Yellow Sign draws power from the Unspeakable One that can bring madness however.

For each time a character looks at the Yellow Sign they must make a Willpower Challenge Roll or gain 1 Insanity. After such a roll the sign in question generally cannot affect a person until they complete a rest.

Possible Modifications:

• Crudely rendered - an especially poorly rendered version of the Sign may actually be hard to see for what it is, and may make it easier to resist the foul powers of the sigil's dark master. Such Signs provide a bonus of 1 boon to the resisting character. 
• Artistically rendered - if the crudest renderings reduce the virulence of the Sign, the most refined and artistic can actually bolster the power if the sigil in the same manner. Such Signs force 1 bane on the resisting character. 
• Forged in Madness - While many cultists of the Unspeakable One are unhinged, only a small handful have fallen utterly into madness. Those that do often degenerate, falling inward until they are little more than catatonic tethers to their fallen god-being. There are those for whom madness provides a strange clarity, and insanity brings genius. Those in such states truly understand madness and comprehend the power of the Yellow Sign. Such understanding also grants strange insights into the creation of the Sign resulting a subtle techniques that distil more power into the sigil.  Such Signs force 1 bane on the resisting character and deal 2 Insanity if the final roll result is 0 or less. 
• Yellow - Just carving or drawing the shape of the Yellow Sign is enough, and yet there is reason to fear a sigil that has been colored, painted, or otherwise been made yellow in color. Such signs force any Banes that roll up as a "1" to be rerolled, or force any Boons that come up as a "6" to be rerolled. In either case the second roll is retained regardless of the value. 
• Cumulative - The Lighthouse of Drac was built with tens of thousands if not millions of bricks, each of which held an inscribed Yellow Sign that added potency to the lighthouse's beacon. Such sigils, when gathered together can amplify each other, or a specific target Sign, granting that sign 1 to 3 banes AND increasing the sanity loss by +1, +1d3, or +1d6. Such groupings of the cursed sigil also affect viewers more frequently and require save in decreasing intervals from 4, 2, and 1 hours, to 30 minutes, 10 minutes, 5 minutes, and 1 minute. Particularly large collections may induce even greater deleterious effects on one's mental health as in the case of Milton's Folly.
• Add one bane and increase the Insanity effect by each order of magnitude.
• Example: A room carved with a dozen simple Yellow Signs (no modifications for quality) imposes a penalty of 1 Bane and does 2 Insanity (1+1) for failed saves. 
• If the room contained hundreds of Yellow Signs this would increase to 2 banes and deal 1d3+1 Insanity on failure. 
• Thousands of such sigils would force a roll with 3 banes and dealing 1d6+1 Insanity. 
• The speed at which such collections can force saves should follow roughly the same cadence with a collection of literal millions of Yellow Signs required to force saves every 10 minutes. (see also Quickened below)

Magic is often used to bolster and enhance the basic Yellow Sign, and the most powerful such symbols often combine both magical enhancement and the mundane enhancements detailed above. Magically rendered signs of the Unspeakable One often derive from profane rituals to the dark god, and gain greater power not only to pierce through even the most willful of minds, but also to tear ever larger portions of one's sanity away.

A magically imbued Yellow Sign gains one or more of the following at the GM's discretion.

• Triggered - A Yellow Sign can be cunningly hidden among other symbols, text, or artwork and lay in waiting for a trigger to unleash its power. A Sign with the Trigger effect only becomes active after a triggering event or time. Prior to being triggered the Sign is entirely benign; afterwards however the Sign acts as normal.
• Quickened - Yellow Signs rendered with the proper magics are extremely difficult to resist, and can push a mind into madness in short order. Yellow Signs created imbued with Quickening magics force a new save on a viewing creature every minute until it or they are removed from the presence of the other. Signs with this magic tend to drive victims to gouge out their own eyes.
• Arcane - Arcane Yellow Signs gain simple degrees of potency, imposing 1-3 banes and/or increasing the Insanity by +1, +1d3, or +1d6. Particularly powerful sigils may impose both, and the most legendary are often Quickened as well. 
• Penetrating - Only the most powerful of rituals (or the most massive collections of sigils working in concert) ever achieve this effect. A penetrating Yellow Sign always deals a minimum of 2 Insanity on a failed roll, but ever worse it is capable of finding cracks in even the most impervious of wills and so it inflicts 1 point of Insanity even on a successful test to resist the power of such a Sign. 

The more powerful the more effort and time to perform such rituals is required. The profane beacon that was built into the Lighthouse of Drac was literally imbued brick by brick and contained millions of sigils each with minor enchantment. The end result was a Yellow Sign beacon that lit the skies over Freeport and could drive men and women mad with a single glance. Thankfully the machinations of Milton Drac and the Cult of the Unspeakable One were stopped, for surely had the beacon been allowed to remain lit it would have become a new manifestation of the Shadow.