I'll Just Eat Some Interest, and All My Creditors Will Go Bankrupt.

After traveling through time and becoming the number one creditor in the world of immortality, I just want to keep a low profile and collect some interest to live forever. Who would have thought that every debt I lent would become an investment that changed the world - when I started collecting debts seriously, I discovered that the Immortal Lord, Demon Emperor, and Demon Emperor who owed the debt had collectively gone bankrupt, and I had become the biggest mastermind behind the scenes in all the worlds.