「虛數之樹」是現今學術界普遍接受的一種宇宙理論。
該學說將不同時空的不同世界比作樹狀結構：每一株枝幹，都是一種世界存在的形式；每一片花葉，都是它們在時間維度中留下的現在與曾經。樹冠因汲取時空維管中無主的虛數能量，而始終存在動態的結構——新芽生長，枯葉脫離，無垠宇宙中上演着無數的誕生與終結…將宇宙結構比喻為「樹」，或許是一種將「虛數之樹」視為生命的態度。
宇宙在「虛數之樹」學說被提出之前，曾因其無法被觀測的性質，被稱為「虛空恆盲之物」；而學說誕生之後，人們便能藉助想像勾勒其作用原理：無主的虛數能量，經過時空維管不停地奔流，在末梢形成了我們所認知的「星系」——即不可勝數的世界。而在世界與世界之間，就像樹葉與樹葉之間存在空間上的阻隔一般，是難以跨越的未知虛數空域。
博識學會一度認為天才俱樂部#2哈那德·龐奇率先提出了「虛數之樹」的起源學說；反覆審度虛構史學家的影響後，現在學界普遍認為#1贊達爾·壹·桑原才是首位提出者。
Imaginary Tree (Theory)
The Imaginary Tree is a theory of the universe widely accepted by the modern scientific community.
This theory describes the various worlds existing in different spacetimes as having a tree-like structure. Every branch is a specific path along which worlds might exist, with every leaf being the marks these worlds have made along the parameter of time. The crown of the tree remains in a dynamic state as it absorbs the masterless Imaginary Energy from the space-time vasculature of the trunk. New shoots grow, withered leaves fall, and endless births and deaths occur among the infinite universe... Describing the universe's structure as a "tree" may be an attitude that views the Imaginary Tree as a life form.
Before the theory of Imaginary Tree was put forward, the universe had been addressed as "a void and indiscernible object" because of its undetectable nature. After the theory was developed, people would visualize its principle using imagination: The untamed imaginary energy surges endlessly through space-time vasculature, and forms at its tips "star clusters" that humans can understand — in other words, countless worlds. The worlds are separated from each other just as leaves are separated by air, between which are unknown imaginary domains that are nigh impossible to traverse.
The Intelligentsia Guild had once thought that Harald Punch, the 2nd member of the Genius Society, was the first to propose the Imaginary Tree origin theory. After multiple assessments on the influence of the History Fictionologists, the scientific community now commonly accepts Zandar One Kuwabara as the person to have proposed it.
