Erythia arrived at Rivers End. She began looking for wood, to carve it into spikes of different lenghts and strengths. Using a small handaxe, she searched for small trees like ashen trees which had shot to long, straight growths nearby, to cut them down and shape them to the makeshift spears.
Once sufficiently sharpened, she would harden the wooden pikes over a campfire, to give them an additional edge.
She looked for the defensive walls and lines, to beset them with the additional defenses, blunt end dug deeply in ground in an angle, where hopefully enemy waves would have a hard time approach and breaching, and even wound or kill themselves in the process.
Afterwards, she began to look around for sand or fine gravel. Should she find it, small pots would be filled. Once heated over flame, as she explained, the pots could be poured over any enemy coming close, causing heavy burns, while being cheaper than boiling oil.
DM Mimic Note: Erythia's efforts bolster the perimeter defenses!