The context is that the family boss has gotten out of prison and decides to try and get arrange a marriage for his daughter (who has been running the 'family business' in his absence). The boss is looking at closing down as he has no son to take over and he doesn't want his daughter to get involved.
I'm not quite sure how the 家族も族だ statement fits into the rest of the sentence. If I had to take a guess at translation in context, it would be 家族 = family, and 族 = bloodline/tribe.
「すまない。お前たちに話すのは初めてかもしれんな。獄中でな、思ったんだ。あの子をちゃんと育てることにしようと。あの子の幸せは何だ。ここで血生臭い戦争させることか。１０年、会わなかった大事な娘だ。引き返せぬ日が来る前に、ちゃんとした子に育ってほしい」
「ですが、きちんと男を取れば」
「そうっすよ。女は駄目だったとしても、その旦那なら」
「別の男の血を入れるということは、族が滅ぶということだ。家族も族だ。ここにいればいつかあの子は修羅となる。それよりも早く、あの子は、外へ出す」
Rough translation below:
Forgive me. This might be the first time I'm telling you guys. When I was in prison, I thought, "I'm going to raise that kid right". What is her happiness? Is it involving her in war and bloodshed? She's my precious girl and I haven't seen in 10 years. I want her to grow up to be a decent kid before it becomes too late.
But if she takes a husband
That's right. If she can't do it then maybe her husband can.
Bringing in another man's blood would mean the end of the bloodline. A family is also a bloodline. If she stays here, one day she will become an Ashura(demon from Japanese folklore that live for battle etc...). I will get her out of here before that happens.
