Also they are using quite the big magic gems, it seems.
Which reminds me, as for the two dragon golems there was a cable attached to them for the sake of providing mana from the outside. (T/N: Wasn’t there a cable attached to only the second one? Huh?; E: Don’t mind the little stuff like “plot details” as you’ll lose the game quicker!)
There also is such a thing as the unmanned workshop where dedicated golems had been working on the repairs. In order to move those, there was a main and sub extra-large magic gem installed as battery.
As for the ancient craftsman Earl Ischrubak, he apparently had a character which was hard to please.
After all he ended up building such an underground for his exclusive refuge investing astronomical amounts of money.