Osric could be considered to have relied on himself for everything, be it the design of his mausoleum or the various settings in it. They were the embodiment of his and his subordinates' wisdom. Brahere did not receive the inheritance of the Immortal King, and did not have peak-level attainments in every field. However, given his unparalleled status among the High Elves, his mausoleum could definitely be considered the crystal of wisdom of the High Elves. Hence, Lin Li was absolutely certain that the danger in Brahere's mausoleum was no lower than that of Osric's mausoleum. In fact, it was probably much more terrifying.
Lin Li, the Supreme Council, and the Alanna Guild of Magic cooperated to explore Osric's mausoleum, during which time the mages of the Alanna Guild of Magic suffered plenty of losses. In addition to the dangerous traps that Osric had laid in the mausoleum, Rosen's wrong decisions were undoubtedly the most critical reason.