Mark of the Adventurer

In Eberron there are dragonmarks.

A dragonmark is a magical symbol that manifests on the skin, but its color immediately differentiates it from any mundane tattoo. A dragonmark is etched in shades of blue, green, and purple so vivid that they appear to glow, though the mark provides no real illumination.
A dragonmark is associated with one or more magical abilities, and a person who carries a dragonmark can exercise these powers. When a bearer invokes the power of a dragonmark, its colors shimmer and flow, and the skin grows warm to the touch. The mark grows warmer each time its power is used over the course of a day; by the time the bearer has expended his full allotment of spell-like abilities, the mark is fever-hot and cannot be used again until it cools. Shapechanging ability and illusions can mimic a dragonmark’s appearance, but usually cannot make it warm to the touch.
In keeping with their magical nature, dragonmarks are not simply skin deep. If a mark is cut or scarred, it reappears as the skin that bears it magically heals. If a warrior loses the hand that bears his dragonmark, the mark will manifest elsewhere on his body. Creatures under the effect of polymorph, wild shape, and other shapechanging effects retain their dragonmarks unless they specifically will them to be hidden.
Nearly all dragonmarked heirs first manifest the least mark of their house. When a character increases her dragonmark’s power, the mark physically expands. A typical least dragonmark covers an area 2 inches square on the skin.
Lesser marks are typically 3–5 inches across, while greater dragonmarks are 6–8 inches. Siberys dragonmarks are vast designs that often cover the bearer’s entire chest or torso. Dragonmarks are tied to bloodlines. The dragonmarked houses are the descendants of the families that first manifested the marks, and a character with a dragonmark can always find a connection to a dragonmarked house somewhere in the roots of his family tree. Though the appearance of marks cannot be consistently predicted, approximately half the children born to dragonmarked parents eventually develop dragonmarks of their own. Common belief holds that parents with powerful marks are more likely to produce gifted children; likewise, children often develop the same powers as their parents.

For Dierde these have never been a thing... until now.
The Wild Cards died one day and Bast made a decision to use this as an opportunity to "kill two ravens". She had them stave off an attack by The Lord of Blades and then they were to work on a long-abandoned Creation Forge (the Arcane Forges of Eberron long used to create Warforged.
They were found to have the mark within them, a mark never known before it would seem.

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There seems to be other "benefits" trying to manifest for the party, but they have not been successful yet...

The Mark of the Adventurer bestows upon them the choice of one new power:

• Advantage on initiaves
• add 1d10 to high and long jump
• add 1 skill proficiency or language
• learn 1 cantrip form any list
• Unarmed attacks add +1d3 damage of bludgeon

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• Barlo (back of neck): Cantrip, Mage Hand
• Bastion (top right hand): Proficiency in Investigation
• Calliope (left ankle): Proficiency in Sleight of Hand
• Sas (top left foot): Cantrip, Eldritch Blast
• Shadow (back of neck): Cantrip, Thorn Whip