「存在的地平線」，博識學會通常將其稱為「虛無視界」，意指它是存在與虛無的邊界。這種間隔界線不屬於物質層面，而是概念意義上「現實的盡頭」。
雖然該視界是非物質的，但部分學者稱，受「虛無」Ⅸ及其命途影響的自滅者能夠觀測到虛無視界，狀如恆星發生全食現象時的形貌；另有研究對此持相反意見，他們認為當該視界如同黑暗的太陽高懸於某人眼中時，便意味着一名自滅者就此誕生。
儘管各執一詞，雙方還是在一點上達成了共識，即：虛無視界會且僅會與觀測者產生相互作用。換言之，一旦某人觀測到虛無視界，便無法停止這一行為，且會不可逆地向着視界邊緣靠近，斷無逃離的可能。一些對「虛無」充滿興趣的學者猜測，自滅者或受其影響的世界將墜入其中，其存在會被永恆固定在不可觀測的視界對側，從現實中抹除。
【記錄印戳】「只有自滅者能夠觀測」，「落入其中的人無一能夠復返」…這些結論難以證實或證偽，或有可能出自虛構史學家的杜撰。
The Horizon of Existence, often referred to as the Border of Nihility by the Intelligentsia Guild, marks the boundary between existence and nihility. This boundary does not pertain to the material realm but signifies the conceptual "end of reality."
Despite the intangible nature of the border, some scholars argue that individuals affected by IX the Nihility and THEIR Path can actually perceive the Border of Nihility, akin to witnessing a total eclipse of a star. Conversely, others suggest that when this border rises like the darkened sun and reflects in one's eyes, it heralds the emergence of a new Self-Annihilator.
Despite this divergence, both sides agree on one aspect: The Border of Nihility solely affects its observers. In other words, once an individual has observed the Border of Nihility, they cannot stop this behavior and will irreversibly move towards the edge of the border, with no possibility of escape. Scholars intrigued by the Nihility speculate that affected Self-Annihilators and affected worlds will plunge into the Border itself, with their very existence eternally fixed to the other side of the unobservable Border, ultimately eradicated from reality.
Record Stamp: "Only Self-Annihilators can observe the Border." "None of those who were drawn by it have ever returned." ...These conclusions remain challenging to verify or falsify, potentially fabricated by History Fictionologists.
