Sicarius

Though, if a Shroud family member were to marry someone completely devoid of magic like Yuu (general), could that perhaps lead to a child with a chance to NOT be born with the curse?? Because Yuu does not carry the gene for magical development.

It’s canon in TWST that not everyone can use magic (Deuce, Book One, Sam’s Shop), but that doesn’t mean someone can’t develop it; it’s just a matter of whether or not it awakens* (only 10% of the population does, canon). An example of this is Ace, whose father is NOT a mage but had two sons who developed magic. It’s unknown if his mother was or was not a mage; however, it’s proof that their father’s lack of magic did not affect their chances of developing magic. There is further canon information regarding “late-bloomers” like Sebek and Kalim, who developed theirs later in life (around teenage years), which implies an average young age for magical development. Information for this is roughly based on Riddle, as he “perfected his magic by age ten, proving to be a genius” (TWST Wiki), thus implying other magical children aren’t in control of their magic at this age, but do have it.

[*The non-mage gene being dominant and the mage gene being recessive.]

Obviously, we know there are exceptions to this, such as Malleus, who is a dragon fae, so automatically he is born with very powerful natural disaster levels of magic, and Riddle, who has an artificially increased magic pool, as confirmed by Idia (Book 6, Chapter 31).

Exploring more into the Shroud Curse, it’s explained in-game through Book 6, that the curse consumes (“burns away”) the blot produced in an individual. So, the curse needs blot to feed on; otherwise, it begins to feed on the individual’s magical energy. This poses a threat to the individual’s health and life.

All this loops back to Yuu, the most magically devoid person to exist on Twisted Wonderland. If Yuu were to marry into the Shroud family and have a child, what does this mean for the Shroud Curse? To determine the chances of this hypothetical child developing magic, I use a Punnett square to calculate it. With Shroud, there’s Mm and Yuu, it’s MM. “M” equals the dominant allele, which is “non-mage”, and “m” equals the recessive allele, which is “mage”. The reason why Yuu is MM is that they have no magic gene, the recessive allele. The results* of the Punnet Square are as follows: 50% homozygous MM, 50% heterozygous Mm, 0% homozygous mm. Based on these findings, it’s a 100% chance of the child coming out as a non-magical person and a 0% chance of developing magic. As stated before, the conditions for the curse are being born with Shroud blood and needing to feed on blot. But only one of those conditions is met: having Shroud blood. Does this mean the Shroud Curse is nullified by the fact that this “Yuu Child” is a non-mage? Or is it because the child has Shroud blood that it’s “forced” to have magic to produce the blot it needs to feed on? If the latter, then what the fuck, that’s an insult to the biology of producing a non-mage or mage individual. However, if it's the former, then this opens up a whole new path of avoiding/escaping the Shroud Curse.

[*Pictured below.]

With the Yuu Child, there’s a high chance of any of their future children being non-mages as well, depending on the genes of the other partner. Once again, I use the Punnet Square to determine the exact chances of this being true.*

1. A Non-Mage with Mm alleles and a Yuu Child with Mm alleles. Results are:

> 25% Non-Mage (homozygous MM)

> 50% Non-Mage (heterozygous Mm)

> 25% Mage (homozygous mm)

> 75% Non-Mage & 25% Mage

2. A Non-Mage with MM alleles and a Yuu Child with Mm alleles. Results are:

> 50% Non-Mage (homozygous MM)

> 50% Non-Mage (heterozygous Mm)

> 100% Non-Mage

3. A Mage with mm alleles and a Yuu Child with Mm alleles. Results are:

> 50% Non-Mage (heterozygous Mm)

> 50% Mage (homozygous mm)

4. A Non-Mage with Mm alleles and a Yuu Child with MM alleles. Results are:

> 50% Non-Mage (homozygous MM)

> 50% Non-Mage (heterozygous Mm)

> 100% Non-Mage

5. A Non-Mage with MM alleles and a Yuu Child with MM alleles. Results are:

> 100% Non-Mage (homozygous MM)

6. A Mage with mm alleles and a Yuu Child with MM alleles. Results are:

> 100% Non-Mage (heterozygous Mm)

As listed above, only 4 out of 6 of the Punnett Squares have a 100% chance of being a non-mage. For a minimal chance of a mage child, a Yuu child with Mm alleles must be with a non-mage with Mm alleles or a mage.

In conclusion, by a Shroud marrying Yuu, whether it be Idia or somehow in some way a completely different, magic-devoid person, they can prevent the spread of the Shroud Curse completely with these children.

[*Pictured below.]