Retrospective Era: the Root of Doom

[Two male protagonists + group portraits + system + time travel + super powers + all villains] The first part of the five-part series of Yggdrasil. The greed of human nature breeds disaster; unruly populations give birth to order; the collapse of civilization will inspire the birth of new civilization, and change only happens overnight. Wanderers in other worlds long to return to their hometown; emotions will not arise in the scorched earth and blood; beautiful flowers are surrounded by thorns; things and people change, and it is the heart or the emotion that changes.