You knew that technically the Mithril school of magic in Eldolan specialized in magical items, but even though you were going to ask about a magical item, it was more about how the item was to be used…how best to draw ichor from the Behemoth.
You spoke to a high elf wizard Tannatar Fendove from the school of Eldritch Masters. He still had connections with Her Eternal Majesty’s Court, despite studying in a city affiliated with the Archmage. He knew of you and the Undaunted, of course. He mentioned that your travels through the Stone Thief had been noticed at the Court of Stars. He said he would describe a way to best draw the ichor out, but in exchange…when (notably, not “if”) you found yourself in the Stone Thief again, to look for a lost observatory that was a project between the three branches of elves and return with intelligence about it. The most common story is that it was lost in an earthquake, but the sages and wizards in the Court have performed other divinations and the moon and stars indicate the observatory is not destroyed as originally thought. Instead, the celestial bodies describe it as moving about…
The only other explanation, then, is that it moves about in the Stone Thief.