Saw/read some new intel on it from gematsu:
■ Yakumo’s Past
Yakumo’s Connection to Mido
Before the world collapsed, Yakumo was once a human being, and together with his comrades were sold off as mercenaries to be used as Mido’s laboratory experiments. Even now that memory remains, as Yakumo seems to have a strong hatred of Mido.
Emily Su (voiced by Yuuki Kuwahara)
A woman who belonged to a private military facility led by Mido and was subjected to cruel experiments alongside Yakumo. During his trying time as a mercenary, Yakumo overcame his suffering with Emily and came to know her as family. After they were separated by the Great Collapse, Yakumo sets out in search of her.
Mido’s Experiments
The memories of Revenants subjected to laboratory experiments by Mido, just like Yakumo. Even after the world collapsed and he was revived as a Revenant, Mido’s cruel experiments continued…
■ Field Introduction: City of Falling Flames
A city burned down by hell fire that never dies out, whose ruins were instantly swallowed up by a whirlpool of flames without any prior warning, that will continue to burn with never-ending momentum until everything becomes ashes.
The roads and buildings have collapsed, and the city is covered entirely in flames. Since you will take damage treading along the burning ground, you should proceed exploring with caution.
Successor of the Ridge of Frozen Souls
A casket of a Successor can also be found on the Ridge of Frozen Souls. Waiting for players inside is a large-horned Lost Successor.