一族

図はCrusader Kings IIIにおける家族関係を示したものです。

この図では、破線で指定されていないかぎり、すべての子供は、合法的で近親婚ではない一夫一婦制の婚姻によって作成されると想定しています。親が1人しか存在しない親子関係では、欠落している親に特別なローカライズ（？）は行われません。

すべての関係は、ユーザーを基準にしています。括弧内の名前は、キャラクターの上にマウスポインタを置いたときに、特に名前が付いたりはしません。

ソース:
game\common\customizable_localization\00relations.txt
game\localization\english

キャラクターの一族（Family）は近親と縁戚の2つの関係者から構成されます。キャラクターの祖父母、両親、兄弟姉妹 (異母兄弟を含む) 、子供、孫は近親者（Close Family） と見なされ、叔父、叔母、従兄弟、甥、姪は 大家族（Extended Family）と見なされます。大抵の場合、一族のほとんどは同じ王朝に属しています。

親または兄弟が65歳未満で死亡した場合、キャラクターは ストレスを獲得します。

評価補正

同じ王朝内の人物、特に近親者には 評価ボーナスがあります。しかしこのボーナスは公の関係に絞られ、秘密にしている家族関係にはボーナスを与えません。キャラクターが別のキャラクターと複数の関係を持つシナリオでは、関連のあるすべての補正が適用されることに注意してください。

他のキャラクターとの関係	評価
親-親	+50
兄弟(異母兄弟を含む)	+25
配偶者(二次配偶者を含む)	+25
同じ王朝	+5

婚姻

婚姻（Marriage）とは、個人的な関係で2人の異性の間の法的な共同体です。婚姻できるのは16歳以上のキャラクターだけです。どちらかのキャラクターが若すぎる場合は、両方の当事者が成人するまで、パートナー候補の2人が婚約することがあります。

配偶者、側室（concubines）、配偶者で多産なものは嫡出子（legitimate children）を持つことができます。普通、婚姻した子供は父親の家に属します。しかし、母系制（matrilineal marriage）では、母親の家から子どもが生まれます。また、婚姻は他のキャラクターとの 同盟の一つの方法でもあります。

宗派の教義（faith's doctrines）は、ある人物が誰と婚姻するか、何人の正式なパートナーを持つか、そして婚姻が離婚に終わるかどうかに影響します。

• 男妾（consorts）、側室（concubines）婚姻の教義は、支配者が配偶者とともに最大3人の配偶者を持つことを認めています。男妾、側室から生まれた子は、 男妾/側室の子 特性を得ます。婚姻とは異なり、側室は同盟をもたらす事はありません。ただし、男妾や側室は離婚することなく自由に破棄することができます。
• 近親婚主義は近親婚を合法とします。
• 婚姻は離婚の教義の法理に従って終了することができます。離婚の対象者は、元配偶者との間に −25の評価「(私と離婚した)」を50年間、相手の近親者との間に −5の評価「(私の近親者と離婚した)」を5年間得ます。離婚した人物は再婚することがあります。

Polygamy

With the Polygamous marriage type doctrine, characters may marry one spouse, and rulers, (depending on their View on Gender doctrine, may additionally have up to three secondary spouses. If two married rulers have the Polygamous doctrine and are allowed to do so by the gender doctrine, they may have multiple spouses each. With the Equal gender doctrine, there is no existing restriction on having the same spouse(s) as another ruler.

Any spouse who follows a Faith that has the Monogamous doctrine will suffer −40  Opinion. Monogamous spouses who were previously in a polygamous marriage (e.g. a secondary spouse was divorced) will still suffer −20  Opinion for 20 years. Any monogamous close relatives will suffer a similar −20  Opinion modifier. Spouses with the Consorts & Concubines doctrine or Polyamory tenet do not suffer similar penalties. When arranging marriages, prospective spouses who would become part of a polygamous marriage and do not believe in polygamy suffer a marriage acceptance penalty of Dynasty.

Rulers receive a penalty of −0.5 monthly piety per missing spouse if they are under the expected spouse amount for their title tier:

Title tier	Expected spouses
Unlanded	1
Baron	1
Count	1
Duke	2
King	3
Emperor	4

Marriage acceptance

In order to successfully arrange marriages with AI characters, the player must reach a marriage acceptance score of at least +1 for the prospective spouses. Below is a list containing all possible conditions that affect marriage acceptance:

Condition	Marriage acceptance
Weak hook	+100
Strong hook	+200, or auto-accept
Promising Prospects Perk	+50 (self) +25 (family member)
Dynasty Glory Perk	+30
Arranging own marriage	−15
Is player's heir	+20 (primary heir) +10 (other heirs)
Desires alliance	Varied
Does not want alliance	−100
Marrying up	+30 for each difference in title rank
Marrying down	−30 for each difference in title rank (if AI is King) −40 for each difference in title rank (if AI is not King)
Opinion	+0.25 per  opinion (round down) with prospective spouse +0.75 per  opinion (round down) with marriage offerer
Wishes well for Lovers	+15
Prospective spouses love each other and AI has compassion greater than zero	+0.25 per AI compassion
Candidate is Lowborn	−20 −120 (if recipient is not lowborn themselves)
Candidate's Level of Splendor	+(Level of Splendor * 5 - 5)
Incorrect marriage (patrilineal/matrilineal)	Varied
Different faith	−10 −25 (faith considered astray or hostile) −1000 (faith considered evil)
Faith does not have polygamy doctrine or polyamory tenet and potential spouse would belong in a polygamous marriage.	−1000
Age Considerations	Varied
The marriage will have Low Fertility	Varied
Unimportant courtier	+10
Important courtier	−10
Prospective spouse is a parent of recipient's children	−25
Player is AI's liege	+40 (general) +60 (marriage with liege)
Valuable claimant	−50
Claimant to one of AI's titles	−50
Intimidated	Varied
Terrified	Varied
Character is dear to AI	Varied
The marriage would be incestuous	−1000
Age of recipient	+(Recipient age − 20)
Spouse councillor - boosted child or heir	+50 +75 (if heir)

Adultery

Having a lover outside of marriage creates a Lover secret. If it is revealed, it may result in the two lover characters gaining the Fornicator and Adulterer traits, depending on the faith's / adultery doctrines. Children known to be born out of wedlock gain Bastard (trait), or Wild Oat if their faith has the No Bastards bastardry doctrine. If a bastard successfully becomes landed, they gain the Bastard founder trait.

Incest

Incest is sexual activity between family members. A faith's Consanguinity doctrine determines the legality of incestuous marriage. Characters having an incestuous relation that would not be allowed in marriage gain the Is Incestuous secret, and if exposed the Incestuous trait. Any form of incestuous relation, legal or not, may risk producing inbred offspring.

The Divine Marriage tenet provides bonuses to incestuous marriages.

Relatives are harder to seduce unless the target character's Faith accepts such an incestuous relation or the seducer has the Subtle Desire perk ( Seducer tree).

Trait inheritance

Congenital traits can be inherited by a character's offspring. Although congenital traits must be visible (active) to provide stat bonuses and other effects, a character may also carry recessive (inactive) traits which are invisible, yet can still be inherited by one's children.

There are some traits that are inherited by children, but do not use the active/inactive inheritance mechanic. In the context of this section, the term congenital trait excludes such traits. It also does not include traits that are non-genetic, yet inheritable.

Chance of active inheritance

The chances of inheriting a congenital trait as an active trait is based on what version (active or inactive) the parents have:

Mother Father	None	Inactive	Active
None	0%	2%	25%
Inactive	2%	10%	50%
Active	25%	50%	80%

Chance of inactive inheritance

If the child does not inherit actively, there is a chance that they will inherit the trait as an inactive trait instead:

Mother Father	None	Inactive	Active
None	0%	25%	75%
Inactive	25%	50%	100%
Active	75%	100%	150%

General logic for trait with tiers inheritance

1. Start from highest trait
2. Calculate active chance. Lower tiers ( including inactive ) count as inactive of the tier. Each level down beyond the first multiplies chance by a define
3. If active, use it; DONE
4. Otherwise, go down a tier, if inactive pretend 1 more parent has that tier active, otherwise 1 more parent has it inactive.GOTO 2

When trying to inherit a tiered genetic trait, and the other person has one of lower tier, we pretend that means they've got the higher tier one recessively, and reduce the chance of inheritance by 20% per tier further down than 1 the other parent's trait is.

When going down a tier, add 40%.

List of congenital traits

The table below contains all genetic traits that use the inheritance mechanism as described above. This list does not contain traits such as  Sayyid, which can be inherited from a character's non-biological parent (in the case of secret bastards), or  Inbred which uses a custom inheritance chance. The natural prevalence column denotes the likelihood of any character being born with the trait if it is not inherited from their parents. For every trait with natural prevalence, the same value can be assumed for random prevalence (i.e. for generated characters). Note that some traits cannot be inherited at the same time since they are incompatible; such traits are indicated if they belong in the same group.

Trait	Natural prevalence (%)	Group	Notes
Melancholic (genetic variant)	0.5	-	If inherited on birth, it is initially hidden.
Lunatic (genetic variant)	0.5	-	If inherited on birth, it is initially hidden.
Possessed (genetic variant)	0.5	-	If inherited on birth, it is initially hidden.
Homely	0.5	Beauty
Ugly	0.25	Beauty
Hideous	0.15	Beauty
Comely	0.5	Beauty
Pretty / Handsome	0.25	Beauty
Beautiful	0.15	Beauty
Slow	0.5	Intelligence
Stupid	0.25	Intelligence
Imbecile	0.05	Intelligence
Quick	0.5	Intelligence
Intelligent	0.25	Intelligence
Genius	0.05	Intelligence
Delicate	0.5	Physique
Frail	0.25	Physique
Feeble	0.15	Physique
Hale	0.5	Physique
Robust	0.25	Physique
Amazonian / Herculean	0.15	Physique
Fecund	0 at birth, unknown for generation	Fertility
Club-footed	0.5	-	Also gained via inbreeding.
Hunchbacked	0.5	-	Also gained via inbreeding.
Lisping	0.5	-
Stuttering	0.5	-
Dwarf	0.5	Stature	Also gained via inbreeding.
Giant	0.5	Stature	Also gained via inbreeding.
Spindly	0.5	Physique (incompatible with good traits)	Also gained via inbreeding.
Scaly	0.5	-	Also gained via inbreeding.
Albino	0.5	-
Wheezing	0.5	-	Also gained via inbreeding.
Bleeder	0.5	-	Also gained via inbreeding.
Barren / Sterile	0.5	Fertility	Also gained via inbreeding.

List of other inherited traits

こちらも参照: Descendant traits

The following list contains all other traits that use a separate inheritance mechanic. For entries without a chance to inherit value for both parents, assume the value for single parent.

Trait	Chance to inherit (%)		Notes
	Single parent	Both parents
Great Pox	10	-
Lover's Pox	10	-
Pure-blooded	15	75	Gained initially through inbreeding.
Inbred	15	-	Gained initially through inbreeding.
Sayyid	100	-	Only inherited from apparent father.
Saoshyant /  Saoshyant Descendant	100	-	When parent has  Saoshyant,  Saoshyant Descendant is inherited instead.
Paragon /  Consecrated Blood	100	-	When parent has  Paragon,  Consecrated Blood is inherited instead.
The Savior /  Divine Blood	100	-	When parent has  The Savior,  Divine Blood is inherited instead.

Inbreeding

Inbreeding is the process of two related characters having children together. For these purposes, related characters are those who share a common ancestor. Such children can be born with negative congenital traits even if neither parent has them, or the Inbred trait in advanced cases. However, there is a small chance for the child to gain the  Pure-blooded trait instead.

In the first generation, small-scale incest such as cousin marriage may not have a massive immediate impact. Nonetheless, repeated instances over successive generations may have an accumulative effect through negative inherited traits and a narrowed gene pool.

Chance of inbreeding

A line graph showing chance of inbreeding based on common ancestors.

The chance of a child being considered inbred can be found from the product of the following:

• Number of common ancestors
• Inbreeding factor based on number of common ancestors
• Inbreeding chance modifier. Currently, only the  Pure-blooded trait provides such an effect.

Common ancestors

The more common ancestors two parents have within four generations (up to their great-great grandparents, and including themselves), the more likely their children will be inbred. Some potential incestuous marriages are noted below. The value provided for common ancestors assumes that ancestors were otherwise non-incestuous and monogamous. Cousins are not removed. Additionally, the value is relative to the breeding couple.

Relation	Common ancestors	Explanation
Full siblings	30 (maximum possible)	By definition, (full) siblings share parents, and thus by extension all other ancestors. The maximum amount of shared ancestors from n generations can be found from [math]\displaystyle{ \text{Max Shared Ancestors} = 2 ^ {n + 1} - 2 }[/math], thus being 30 from 4 generations. Or, written out, full siblings share both parents (2), two sets of grandparents (4), four sets of great grandparents (8) and eight sets of great-great grandparents (16).
Parent-child	15	In the case of a partner being the other partner's ancestor, they are counted as a common ancestor. As a result, the common ancestors are the following (perspective is child/parent): parent/self (1), one set of grandparents/both parents (2), two sets of great-grandparents/standard grandparents (4), four sets of great-great grandparents/great grandparents (8). Note that the parent's great-great grandparents are the child's 3×-great grandparents, and are therefore not counted.
Half siblings	15	They share one parent, and therefore share only half of the maximum amount of ancestors. Alternatively, they share one parent (1), one set of grandparents (2), two sets of great grandparents (4) and four sets of great-great grandparents (8).
First cousins	14	First cousins share grandparents (2), two sets of great grandparents (4) and four sets of great-great grandparents (8).
Uncle-niece/aunt-nephew	14	Similar to first cousins, but rather than sharing grandparents, the sibling's grandparents are the uncle/aunt's parents. Note that since the uncle/aunt's great-great grandparents are the sibling’s 3×-great grandparents, who are 5 generations away from the sibling’s perspective, they are not counted.
Second cousins	6	Second cousins share one set of great grandparents (2) and two sets of great-great grandparents (4).
Third cousins	2	Third cousins share one set of great-great grandparents.

Inbreeding factor

The inbreeding factor for a given amount of common ancestors can be found through the following:

Common ancestors	Factor	Chance before modifiers
0-14	0.33	Between 0% and 4.62%
15-16	0.75	Between 11.25% and 12%
17-19	1	Between 17% and 19%
20-21	2	Between 40% and 42%
22-30	3	Between 66% and 90%

Effect of Pure-blooded on inbreeding

The Pure-blooded trait provides −50% chance of inbreeding per parent. If two parents have the Pure-blooded trait, this effect combines to no chance of gaining traits due to inbreeding. Note that this excepts the chance of gaining the Pure-blooded trait naturally, as well as the inheritance of such traits via parents. It is unknown whether the Pure-blooded trait has an effect on gaining the Inbred trait.

Traits gained from inbreeding

The following traits may be gained from inbreeding. Note that these general inbred traits may also be gained naturally and are congenital. Offspring only have a chance to gain these traits as a result of inbreeding if their parents do not possess any of these traits (plus the  Inbred trait). The traits below appear equally likely.

•  Barren / Sterile
•  Scaly
•  Club-footed
•  Wheezing
•  Spindly
•  Giant
•  Hunchbacked
•  Bleeder
•  Dwarf

Additionally, there are two traits that may only be gained initially through inbreeding and have special requirements: Inbred and Pure-blooded.

Inbred

The  Inbred trait may be inherited from one's parents. It may also be gained if a character with a general inbred trait has children with someone with whom they share a common ancestor. The chance of gaining the Inbred trait as a result of this is unknown. Note that even with highly incestuous marriages, no children will gain the Inbred trait if the parents do not possess any of the enabling traits.

Pure-blooded

The Pure-blooded trait may be inherited from one's parents. Otherwise, it may be gained naturally. Similar to the chance of inbreeding, the chance of gaining the  Pure-blooded trait naturally is based on the number of common ancestors, multiplied by the corresponding level factor for that amount of common ancestors:

The inbreeding traits overwrite the  Pure-blooded trait, thus the chance for a child to have the  Pure-blooded trait by gaining it naturally is equal to the chance of not getting an inbreeding trait multiplied by the chance to get the  Pure-blooded trait. This chance is maximized at 22 common ancestors for a value of 2.24%.

Common ancestors	Factor	Final chance	Chance after Inbred roll
0-19	0	0%	0%
20-21	0.15	Between 3% and 3.15%	Between 1.8% and 1.83%
22-30	0.3	Between 6.6% and 9%	Between 2.24% and 0.9%

As a result, parents must have at least 20 common ancestors for a child to gain the  Pure-blooded trait naturally. This does not apply to inheriting it from parents.

References

メカニクス