New Headcanon Book

Memories of the Five Heroes (Dawn of corruption)

Memories of Orzwald : "In the echoed worlds, the corruption has faded, what is replaced is the devotion to the lands, a name transcends time and space"
Defeat Apothus and choose to join orzwald in the hunt against demons and corruption, unlocks a new ability - Demon hunt, requires low/zero corruption

Memories of Rynel Ashar: "A Hunter soon chooses it's own path, one that will lead to victory beyond the impossible reach, the wolf name is heard beyond time and space"
Defeat Apothus and Defeat Corrupted Rynel, and spare him, this in exchange allows Rynel to become the hunter god

Memories of Yumaro taisen: "He sacrificed himself to seal the realm of corruption alongside nyx, but his soul, proved too powerful for even the gods to recognize, he becomes a God of pure souls, now the name is mentioned beyond time"
Defeat Apothus and if high corruption and yumaro taisen learns "Soul Art - Memorial future", this in return resets the corruption, bring the bastion back to normal, and unlock the new land "Pandemonium - the land of shattered memories"

Memories of Riku Nekoyama: "He gambles fate, and like a puppeteer, he chooses his own destiny, a name transcends beyond time"
Defeat Apothus and if you got the golden god dice, Nekoyama will fused with the PC to become the god of luck, but if corruption is high, this is replaced with "God of Luck and Corruption"

Memories of Voldar jin: "He gave up his life to purify the land in the name of the god, Albar, though in doing so, he becomes the vessel and barrier guardian between the realm of corruption and the realm of mortals, his name transcends beyond time and space"
Defeat Apothus and if voldar corruption is above 20 or more, Voldar soon pushes PC away from the ascension and let him ascend, thus becoming the barrier to prevent nyx awakening

Memory of the Soul Linker and Paladin : "Both fused as one, their sacrifices outdid what nyx has foresaw. Their name transcends both time and space, this is the power of Voldar and Yumaro"
Defeat Apothus and if you bring voldar and yumaro taisen to the fight, voldar jin decide to sacrifice himself but yumaro taisen joins in as well.

Also this unlocks achievements.

Memories of the Demon Hunter - Unlock Orzwald ending

Memories of the Hunter - Unlock Rynel ending

Memories of the soul Linker - Unlock Yumaro ending

Memories of the Gambler - Unlock Riku ending

Memories of the paladin - unlock voldar ending

The Paladin of Souls - Unlock voldar and Yumaru ending