The Deluge is a corrupted and mutated entity descendent of an ancient race called the Yinnari. It/they are responsible for the first and second Great Cataclysm that befell the galaxy.
To everyone bearing witness to the Deluge, they are a horrifying force of nature, a true eldritch horror made manifest, consuming all life it encounters – unrelenting and immeasurable. However, in the Deluge’s own [hive] mind, they are a benevolent entity bringing all other sentient life into the blissed fold of the communion. Alone, one is constrained by their mortality and personal competence. However, through communion, they lose the worries of their individuality and become ‘embraced’ by the greater whole – their consciousness and memories now part of the collective.