I recall the brothers say they're from a farm outside of BG, and by extension, so would Mayrina. We're given some details, so we'll likely get to visit. Much of 'Baldur's Gate' is outside the city walls.
Now you've got me curious about Green Lantern, I'll look up his motivation.
Ethel also seems to be aware her plot doesn't work well if you don't play along. She curses, kills the now useless brothers and departs. But your typical murder-hobo is going to take that as a sign she's walking XP with cool loot. Probably the worst thing she could've done, pique the interest of such a dreaded monster.
