Prehistoric: a Child Bride at the Beginning

''Invincible flow'' The otaku Qin Xuan took a great-level child bride and traveled to a time when the human race was just born. Originally, I saw that the 'system' was relatively rubbish, and I just wanted to live forever. But during a breakthrough, he found out about the overbearing contract he made with his young wife, and he could actually become immortal! Due to various reasons, he embarked on the path planned for the human race. With constant travel, a similar but different prehistoric world was revealed.