The Apocalypse Yakuza

Mafia Boss Genichirou Tokada Inukai, Asia's largest underworld organisation leader, completes 108 years of natural life. His inheritance going to his granddaughter totals to 5000 trillion ¥ (5 quadrillion yen or 46,560,140,000,000.00 USD), approximately 360 times the assets of the founder, roughly 17 times the national budget of Japan. Yet the desire of this unscrupulous daughter who has a non-standard financial power is to… make friends ? --- Alt synopsis: What do people want or do if they receive 5000 trillion yen all of a sudden? A youth comedy in the dark society. Chifuyu Inukai solves all things with the power of money, starting a comedy of unprecedented scale (of spending) in all history of manga.

A boy wakes up in a strange room and finds a girl passed out with him. They find out they both have weird collars on. The boy has a phone which seems to be connected to the people behind this. They want them to do what!?

Kawasaki was destroyed by a giant monster that suddenly appeared. In a city abandoned by the government, the only person fighting the monsters is a yakuza who was based in Kawasaki.