Still not a permanent solution. People get old and die after all. Even in the most "optimistic" scenarios, they have about 100 years to the end of the world.
Subjecting them to constant stress results in shorter lifespan and implied 110-Montauk would greatly shorten hers. Could be as low...
This part was the most Mary Sue like chapter of them all.
MC: Oh no, you have a nefarious scheme! Please don't, why don't we be friends instead?
Elf: ... sounds good.
But she's cute so it's ok. Lol.
Actually, it might have been interesting to have her skin change and use it as a plot point about colour discrimination.
See who changes their attitude before and after, and all that.
I'm of the opinion they should have gone the other way. Make her items and spread them to trusted people. Have her create defensive items to prevent assassinations, detect disloyalty and infiltrators, equip the house's loyal guards. Full audacity cheat mode!
Have eyes but cannot see Mount Tai - 有眼不识泰山
Do these idiots not have any idea what the general abilities are for the various levels? Master/Grandmaster/Innate etc. ?
Just from his solid projections, they should be able to tell he's at least grandmaster.