The events in this card's artwork are a continuation of the events depicted in "Void Feast".
Purusha is a Sanscrit word with many meanings, most significantly being the name of the entity that became the origin of all things in Hindu mythology, described as a giant with 1000 heads, 1000 eyes and 1000 legs.
Aion is a Greek word meaning "time"/"age"/"era" and a word Plato used to refer to "eternity". It refers to the true god's metaexistence in Gnosticism and its an existence that opposes to the Archon (which is the fake gods, such as "Sophia, Goddess of Rebirth").
The kanji 「魂源への影劫回帰」 (Kongen e no Eigō Kaiki) in this card's Japanese name roughly translates to "Eternal Return to the Soul's Origin".
The kanji 「魂源」 (Kongen) is a homophone of 「根源」 (Kongen, "Origin"), with 「魂」 (Kon, "Soul") substituting 「根」 (Kon, "Root").
「影劫回帰」 (Eigō Kaiki) is a homophone of 「永劫回帰」 (Eigō Kaiki, "Eternal Return"), with 「影」 (Ei, "Shadow") substituting 「永」 (Ei, "Eternal").
Eternal return is the concept proposed by Friedrich Nietzsche in Thus Spoke Zarathustra, believing that humanity has no previous lives or next lives, but repetitions of the current life.