Marriage within the same family or group in accordance with a cultural custom, tradition or law would be endogamy.
Marriage within one's own family, clan, etc., would be called intermarriage.
Incest.
Incest
He married to Lina von Osten, a member of a nationalist, anti-Semitic family.
Of course. The sponsor's daughter is not a member of your family. You may marry her in the same way as any other Catholic.
Every family member should know that you shouldn't marry your siblings or first cousins. Research has proven that children of close family members tend to have debilitating disorders.
A blended family .
He married to Lina von Osten, a member of a nationalist, anti-Semitic family.
It depends on the family member. If it's a cousin, that's one thing. A sibling, parent, son or daughter, etc.--not OK.
A family tree
a chart that tracks which family member has a certain trait is called a pedigree.
Nepotism!
It's called incest
Patriarch
Depends. Maybe the family will want to carry on with their tradition by marrying off each other to a family member e.g. Cousins