It <p><img alt="" src="https://www.tibiawiki.com.br/images/d/de/Ring_of_Secret_Thoughts_%28Charged%29.gif" style="height:32px; width:32px"> <span style="color:#f39c12"><em>(Charged)</em></span></p><p>It is used for the kilmaresh questline, you need it in to charge it at one part of the quest when you are going into and then you will have to use it in order to go into the Ambassador's Brain :)
The :)<br><br>The reason why you see so many of them in adventurer's guildhall is because players keep looting the ring from the boss.
It serves no daily boss.<br><br>It doesn't really serve much purpose if you have completed the quest, unless you want to wear it or use it as decoration ;):)</p>