Apollyon's shikai form is that of a double edged katana with hook shaped serrated teeth on its backside. The hand guard of Apollyon is shaped like a pentagram and it has a short black-steel spike that protrudes from the bottom of the hilt. Its release command is "open the gates of hell".
- Black Fire - Generates black balefire that incinerates objects on contact. The fire does not radiate energy but rather transfers its full energy to the target on contact. Andoryuu is able to manipulate the fire directly, moving and shaping it according to his will.
- Unleash the Dark Soul - When Andoryuu slays an individual that person’s spiritual energy is formed into a shadow creature that is under Andoryuu’s control. These creatures can cause devastating physical wounds as well as drain spiritual energy from their opponents.
- Dark Prophecy - Andoryuu experiences phantasms of future injuries, including the pain. This allows Andoryuu to dodge upcoming attacks with ease however overuse can cause Andoryuu to become incapacitated with pain. This technique can also have psychological ramifications resulting from repeated use.
- Phantom Pain - the victim experiences an illusionary attack which causes them to feel pain. The subjective experience only lasts a few moments, however objectively no time passes. Weaker victims can be incapacitated by this technique. For this ability to work Andoryuu must be within 15 feet of his intended target.
- Apportation - Andoryuu is able to summon Apollyon to his hand regardless of the distance between him and Apollyon. This ability can be used even in Apollyon’s unreleased state.
- Dark Deal - Barbs shoot out from the hilt of the sword piercing Andoryuu’s hand and feeding on his blood. In exchange for his blood Andoryuu’s powers increase exponentially giving him increased strength, speed and spiritual energy.
- Dark Rejuvenation - Even if Andoryuu’s body is destroyed, so long as Apollyon remains intact, he will not die. His essence will become infused with Apollyon’s and the next person to grab Apollyon’s hilt will be transformed into Andoryuu. When this happens, barbs shoot from Apollyon’s hilt and bond to the victims hand before transforming the victim into Andoryuu. The more spiritual energy the victims has the longer this process will take. The only way to stop the transformation is to cut off the hand of the victim before the transformation is complete.
When Apollyon’s bankai is released the pentagram hand guard glows red and disappears in a flash of light before forming a large energy pentagram, from which demons can be summoned. Once this is done Apollyon loses all of its previous shikai abilities and is basically a normal sword.
Andoryuu did not achieve his bankai in a traditional way but must fullfilll a requirement in order to use it. As such, every time he uses his bankai he must first meet this requirement by killing five people and offering the dark souls that are created from their deaths. When this happens the dark souls each take a point on the pentagram and channel all their spiritual energy into it, resulting in their destruction.
Apollyon's bankai allows Andoryuu to summon one of the following seven demons to battle, each one representing one of the seven deadly sins. The following demons represent pride, greed, lust, envy, gluttony, wrath and sloth respectively.
- Lucifer - Appears as a giant angel with a black wing on the left side of his body and a white wing of the right side of his body. He has the ability to manipulate darkness and light and wields a long sword.
- Mammon - Appears as a giant horned demon with the lower body of a snake and wields a three pronged spear. He has the ability to absorb any spiritual energy that is directed towards him and can also absorb the energy of anyone he kills. His hide is immensely durable and hard to pierce and becomes increasingly strong with the more spiritual energy he absorbs.
- Asmodeus - appears as a giant man with the heads of a ram (right head), a man (center head) and bull (left head). He wields a lance that is capable of piercing almost anything and is able to breathe fire.
- Leviathan - Appears as a giant sea serpent with sharp teeth and poison saliva. The saliva itself is a powerful corrosive agent that is capable of dissolving stone. Its hide is also extremely tough and difficult to pierce and it is capable of flight.
- Beelzebub - Appears as a giant monstrous fly with the ability to eat almost any material and separate into swarms of smaller flies. These smaller flies share Beelzebub’s abilities and hunger and can be devastatingly voracious. The more Beelzebub eats the larger he grows and the more flies he is capable of splitting into. The smaller flies are still capable of growth though they are not able separate themselves. In order for Beelzebub to separate into a larger number of flies than he did originally, he must first reassemble himself into a whole before separating into a larger group, this process leave him temporarily vulnerable. When first summoned he appears about the size of a school bus, but is capable of growing to much larger sizes.
- Amon - Appears as a giant fire-breathing wolf with a venomous serpent for a tail. The fire he breathes is capable of melting cold stone to slag and the venom from his tail is devastatingly deadly. He is capable of seeing both from the eyes on his head and his tail, making sneak attracts extremely difficult.
- Belphegor - Appears as a giant bearded demon with horns and has the ability to slow time down around him, causing him to appear to be very fast (he is in fact quite slow). The wielder of Apollyon is the only person immune to Belphegor’s ability, other than Belphegor himself. The effective radius of Belphegor’s ability is approximately 150 meters.
Apollyon's spirit appears as a dark winged angel that shines with black fire and holds the keys to hell.
The wielder of Apollyon is Andoryuu, a young man with light, plainly cut, brown hair, blue eyes and glasses. He is soft spoken and shy. Though appearing to be kind, timid and weak Andoryuu has a darker nature that few know about. Though he tries to deny it, his zanpakuto is a reflection of his dark nature, and so he often does not carry it. Despite this Andoryuu is in constant contact with his zanpakuto through its apportation ability, which he considers a curse despite its obvious usefulness. As a side effect of Apollyon’s apportation ability Andoryuu is also in constant contact with the spirit of his zanpakuto, which constantly temps Andoryuu to act on his dark nature.
Andoryuu joined the fourth squad to avoid combat and to repress his dark nature. He excels at kido, in part because he dislikes using his zanpakuto. Despite being a member of the fourth squad, Andoryuu is not hassled by members of other squads who, for some reason, are inexplicably afraid of him.
Despite his best efforts Andoryuu is unable to completely disguise his nature from other people, as he frequently gives them the creeps. This has manifested as wounded individuals attempting to leave his care in order to avoid him. Though this fear is unsupported by Andoryuu's behaviour he seems to radiate malicious intent.