Arapachana Manjushri is a meditational deity in Vajrayana Buddhism. He is generally classified as either Kriya or Charya Tantra. In terms of function Manjushri is typically categorized as a wisdom deity - meaning a meditational deity that promotes the increase of wisdom, knowledge, memory, language skills, etc. There are several different forms of Arapachana Manjushri and there are several forms of Manjushri that look like Arapachana but are not.
84000: Translating the Words of the Buddha: Siddhaikavīra Tantra (Siddhaikavīratantram, dpa’ bo gcig pu grub pa zhes bya ba’i rgyud kyi rgyal po chen po)
Prajnaparamita Sutra The Large Sutra on Perfect Wisdom
I, 9, 15. The Equipment with the Dharanis
And again, Subhuti, the Dharani-doors are the great vehicle of the Bodhisattvas, the great being. Which are they? The sameness of all letters and syllables, the sameness of all spoken words, the syllable-doors, the syllable-entrances. What then are the syllable-doors, the syllable-entrances?
1. [A]: The syllable A is a door to the insight that all dharmas are unproduced from the very beginning (ady-anutpannatvad); 2. RA is a door to the insight that all dharmas are without dirt (rajas); 3. PA is a door to the insight that all dharmas have been expounded in the ultimate sense (paramrtha); 4. CA is a door to the insight that the decease (cyavana) or rebirth of any dharma cannot be apprehended, because all dharmas do not decease, nor are they reborn; 5. NA is a door to the insight that the Names of all dharmas have vanished; the essential nature behind names cannot be gained or lost.
(The Large Sutra on Perfect Wisdom. Translated by Edward Conze. Luzac & Company, London: 1961. Page 148. University of California: 1975, 1984. Page 160).