GREETINGS AGAIN! I asked ya before but im not totally sure how tumbler works. New, but u asked more questions in the notes/comments of my first one
Hiya! I've seen them, but didn't have time to answer them yet. Iiiiiin any case, let's get to that, shall we?
Arachne very much tricked another of their species into giving them their admin powers briefly, before killing that other one and keeping the powers for themself. As for how the transfer works, it is quite simply done by telling the universe/the world it needs to listen to someone else for a bit. Of course, this would go paired with unlinking one's soul/code from the part that gives the admin power, and linking it back up to the new admin, which can be anywhere between unpleasant and outright painful as it's like losing a sense.
Arachne had some difficulties with setting laws because they were changing things in ways they definitely weren't supposed to be changed, as well as that they were (mostly) not using a specialised tool for doing admin stuff (a communicator) and doing it by hand instead. Thirdly, Xisuma was better at it because of the very simple reason that he's done that specific task more often and as such had practiced it more.
As for how long they've been in the world... Well. Since long, long before the Hermits got there, I have no exact number for ya ;)
Whether Grian and Mumbo become friends again will remain a mystery until I've finished the first two epilogues (almost done with the first one, then again, I've been almost done for like a month now)
As for the text spam, you're totally good! I don't mind it in the slightest :D