Babandohara

Year 120 is approaching, and everyone knows what that means.
Without hesitation, Yuki Gasai, an anonymous figure, hosts and legalizes the Center - a broken match in which forces a number of teens ( specifically those of the sibling ratio ) to kill off those who share no blood relation until the last family children stand and survive to year 126.
Many new contestants have been welcomed to the Center, but neither thinks so well of themselves, and hold a perk that cripples them for who knows how long.