This journal was discovered in the Planar Beacon and seemingly belonged to the mage Thalivar himself. The journal seems to be exactly that, mostly going over the thoughts and day to day issues Thalivar had to deal with. Due to it being written for himself (and also in ancient Elven) it is often hard to extract meaningful information from it.However after examination from Gallio Elibro one can find some explanation of what the Planar Beacon actually was used for. The tower had been constructed by the Enclave Of The Evergreen to function as a "Planar Beacon". The Beacon's purpose was to stop interplanar travel from other planes of existence into the material realm mostly as a deterrent as any who would try would be instead be taken by the tower and frozen in place.
However Thalivar started using the tower for a secondary purpose, flashing the beacon on and off in order to draw and capture more creatures to study. When confronted about this behavior by the Conclave Thalivar explained that he had to study these interplanar creatures if they wanted to know how to fight them. The journal goes in length detailing some of the captured experiments, often ending in their death or banishment. Any objections the Enclave Of The Evergreen had vanished once Thalivar discovered the Ruinstone, an item found upon the body of a fey humanoid. WHile nothing is mentioned about the fate of that humanoid it was quickly discovered that the stone had the ability to warp reality to suit the wielder's wishes.
However Thalivar was not able to study it sufficiently as an Enclave representative quickly came and took it away, citing it as of vital importance for the defense of the realm. Outraged Thalivar wrote that he was planning to repeat the sequence that captured the fey humanoid the first time in order to find another stone. The older entries stop here.
The newest entries have been made in the last few days judging by the dates and the freshness of the ink reveal that the later entries have been made in the last few days. They detail how Thalivar was in a haze, his tower made to look ruined by an illusion. He mentions an explosion but his writing here is frantic and hard to make sense of. He writes that he is drawn to a pile of rubble in the ruined chamber under the skeleton of an odd creature but each time he draws close to the rubble, a terrible dread would hold him back. Thalivar often mentions his faerie servant Soapwort and how he wishes that he was here to either assure him that he’s dreaming or help him understand what was going on, but the faerie never turned up no matter how much he searched. The entries end with a prayer that these nightmares will end soon so he could resume his studies in peace.