I have a schizo theory that Nikke began life as egghead's self-insert fanfiction where he marries and impregnates 2B, and he essentially pitched a modified version of this fanfiction to SU bigwigs for their next gacha. They even got 2B's JP voice actress to play JP Rapi.

>Nihilister said it would take 2 weeks to reach Lilith's body on foot.
>The average human walking speed is 3 miles per hour.
>Ergo, they could cover 72 miles a day, and 504 in a week, assuming they don't stop to rest.
So Lilith's body is about 1008 miles (1622.219 km) away from Eden.

Let's say Nayuta and Nihilister left Eden at around evening. Nihilister estimated they would now reach Lilith's body by next morning on Mantra. Say, 12-15 hours from travel start. That means Mantra travels between 67 (107.8 km) and 84 (135.2 km) miles per hour.

Not as fast as I thought.