Mitsuhide Akechi

Mitsuhide Akechi (明智=光秀, Akechi Mitsuhide) is the main antagonist of Part II of Bleach: Rising Phoenix. Initially disguised as a lowly ramen bar owner, Mitsuhide is the real murderer of Yuu Kimitsu. While he initially appears to be a mentor of sorts to Gai Nagareboshi, helping him deal with keeping the secret of his time-travel from his companions, supplying him with historical recounts of the Soul Society's creation; the time of the Mototsu in particular and explaining the basics of time-travel, it is revealed that he is actually wiping Gai's mind of the information concerning Yuu's death every time he reaches the scene; thus explaining why each time Gai attempts to remember the event, it is always inconsistent; which concerns Mitsuru Inazuma.

The reason he aids Gai is revealed to be that he wants Gai to awaken Harafumei by the way of messing with the space-time continuum; who is documented in legends to be the strongest being in existance. Thanks to Kyomu's special ability, Mitsuhide seeks to take Harafumei's power for himself and become a being "beyond the Soul King, an omnipotent being with dominion over everything", with his true purpose being to rewrite reality and reincarnate in the living world, making it "hell on earth".

Zanpakutō
Kyomu (虚無, Nothingness) is the name of Mitsuhide's Zanpakutō. When sealed, it takes the form of a bokken, a wooden katana.

Shikai: In Shikai, Kyomu becomes at katana with a long, turquoise handle with a gold pommel. Its guard is blue-green and decorated with swirling, yellow patterns. The blade itself is quite large. Although classed as a katana, it is related closer to the zanbatō, or even to the nodachi.

Shikai Special Abilities: Kyomu allows Mitsuhide to manipulate nothingness, granting him a multitude of vaguely related abilities, such as teleportation, flight, creating energy barriers to shield himself, form weapons out of negative energy, create copies of himself, summon torrents of white and black thorns and generation of negative energy. Kyomu's ability has a sort of "reverse-reality warping" property, instead of being able to bend reality, it destroys reality. Mitsuhide boasts that Kyomu's special ability allows him complete authority over "Oblivion" (忘却, Bōkyaku). Bankai: Zettaiteki Kyomu (絶対的虚無, Complete Nothingness) is the name of Mitsuhide's Bankai.
 * Kōshō Mōkō (紅象猛攻, "Rouge Phenomenon Ferocious Attack", alternately "Shining Onslaught"): Mitsuhide unleashes a blast of highly condensed scarlet negative energy through Kyomu in the shape of a spinning 'X', sending everything it touches into oblivion. When used against Haruko Kiseki, this attack was able to obliterate several buildings within Rukongai, and it would've completely consumed Rukongai, if Mitsuru hadn't intervened with his significantly superior Eisha Shūrai.
 * Translocation (転座, Utateza): Mitsuhide teleports by deleting the space in-between his target and himself. Utilizing this technique, Mitsuhide can move faster than light-speed.
 * Creation (創見, Sōken): Mitsuhide can create a variety of desired weapons and tools out of pure solid negative energy.

Bankai Special Abilities: Not Yet Revealed.
 * Suffocation (窒息, Chissoku): Mitsuhide sends the surrounding air and oxygen into oblivion, causing his opponent to suffocate.
 * Black Hole (黒い穴, Kuroiana): Mitsuhide amasses negative energy around his blade, forming an enormous black hole, which he launches at an opponent. The black hole engulfs the enemy and crushes them within its singularity.
 * Absolute Zero (絶対零度, Zettaireido): Mitsuhide completely halts the movement of electrons with super-cold air at absolute zero, completely freezing anything and bringing his opponent's vital functions to a screeching halt, before converging the electrons and releasing them as a super-ray of light at his foe.
 * Vacuum (空白, Shinkū): By planting his blade into the ground, Mitsuhide is able to create hard vacuums that cause earthquake-like disasters.
 * Bond Destroyer (債艦, Saikan): With a single slash, Mitsuhide can obliterate the bonds of most Kidō and some Zanpakutō abilities, causing them to collapse. This is without a doubt, Mitsuhide's deadliest ability.