Fudō Myōō

Acala or Achala (Sanskrit: अचल, "The Immovable", IPA: [ˈɐt͜ɕɐlɐ]), also known as Acalanātha (अचलनाथ, "Immovable Lord") or Āryācalanātha (आर्याचलनाथ, "Noble Immovable Lord"), is a wrathful deity and dharmapala (protector of the Dharma) prominent in Vajrayana Buddhism and East Asian Buddhism.
Originally a minor deity described as a messenger or acolyte of the buddha Vairocana, Acala later rose to prominence as an object of veneration in his own right as a remover of obstacles and destroyer of evil, eventually becoming seen as the wrathful manifestation of either Vairocana, the Buddha Akṣobhya, or the Bodhisattva Mañjuśrī. In later texts, he is also called Caṇḍaroṣaṇa (चण्डरोषण, "Violent Wrathful One", IPA: [t͜ɕɐɳɖɐˈroːʂɐɳɐ]) or Caṇḍamahāroṣaṇa (चण्डमहारोषण, "Violent One of Great Wrath", IPA: [t͜ɕɐɳɖɐmɐɦaːˈroːʂɐɳɐ]), the names by which he is more commonly known in countries like Nepal and Tibet.
In East Asian esoteric Buddhism, Acala is classed among the Wisdom Kings (Vidyārāja) and is preeminent among the five Wisdom Kings of the Womb Realm. Accordingly, he occupies an important hierarchical position in the Mandala of the Two Realms. In China, he is known as Bùdòng Míngwáng (不動明王, "Immovable Wisdom King", the Chinese translation of Sanskrit Acala(nātha) Vidyārāja), while in Japan, he is called Fudō Myōō, the on'yomi reading of his Chinese name. Acala (as Fudō) is one of the especially important and well-known divinities in Japanese Buddhism, being especially venerated in the Shingon, Tendai, Zen, and Nichiren sects, as well as in Shugendō.
Acala has been worshiped throughout the Middle Ages and into modern times in Nepal, Tibet, China and Japan, where sculptural and pictorial representations of him are most often found.

Origins and development
Acala first appears in the Amoghapāśakalparāja Sūtra (Chinese: 不空羂索神変真言經; pinyin: Bùkōng juànsuǒ shénbiàn zhēnyán jīng, translated by Bodhiruci circa 707-709 CE), where he is described as a servant or messenger of the buddha Vairocana:The first from the west in the northern quadrant is the acolyte Acala (不動使者). In his left hand he grasps a noose and in his right hand he holds a sword. He is seated in the half-lotus position.
More well-known, however, is the following passage from the Mahāvairocana Tantra (also known as the Mahāvairocanābhisaṃbodhi Tantra or the Vairocana Sūtra) which refers to Acala as one of the deities of the Womb Realm Mandala:…