Lots of people horde codestones. They pick them up when the price is low, shove them in their SDB, and wait for a new plot, when the prices soar. It appears that the current plot may have ended, and ended quite abruptly, well before anyone thought it would end. So my guess is that this guy might be panicking and attempting to sell off what he has before the prices of codestones plummet. Because they will plummet once it is known for sure that the plot is over. And 800 codestones might seem like a lot, but, well, not really. Especially if he has been hoarding them ever since the last war. I am a negg seller. That's pretty much all I sell. And right now, I have 1783 of them in my SDB. About 200 of those are reserved for someone. But the rest were picked up when the prices were low and will be put in my shop as my shop supply gets depleted. I don't put all of them out at once because I have learned that by putting large number out, it really can cause the market to plummet.
Tested made this fabulous set for me!!! Isn't it great?