The Tengan (天国の眼; lit. Heaven's Eye) is Kekkei Genkai appearing in the Land of Blizzards only recently. The Tengan is a diluted and mutated offshoot of the Shingan, through several generations. The Tengan has only two known possessors, Ayase and Mikiko Mizusaka. Whether the Tengan is a passable Kekkei Genkai or a unique ability restricted to them alone is unknown.
The Tengan, unlike its ancestor, the Shingan, is not a mental ability that uses its wielder's eyes as a catalyst, but is a true doujutsu. However, the Tengan is a highly bizarre ability, even by the standards of the variable shinobi world. Because of these abnormal characteristics, it is strongly suggested that the Tengan is exclusive to Ayase and Mikiko, or to twins in general. The Tengan appears only in one eye, and the eye it appears in is opposite to the other twin's. The Tengan also only functions when both eyes are in proximity of each other, though the range is quite significant. The Tengan appears a glowing azure-blue, and also seemingly melds the minds of the two wielders together.
The Tengan's abilities are considerably different from the Shingan, although they are arguably just as formidable. The Tengan technically allows one ability in its user, though due to the minds of the wielders being merged, it effectively grants two.
The Tengan in the user that possesses the right eye grants them telepathy. The user is able to commune with the other twin through the Tengan's telepathy, and scan the memories or sense thoughts of others. This ability allows the user to literally read and anticipate their opponents next move, making it seem that they have the ability to see the future. The Tengan in the user that possesses the left eye grants them empathy. The user is able to sense the emotional state of another, as well as their intentions and innermost feelings. This ability allows the user to taunt and mentally break or waver an opponent by sensing their emotions, and acting accordingly.
Used together, however, the Tengan has an even more powerful and frighteningly ability. When the right and left Tengan eyes are used in conjunction, the users are able to induce powerful hallucinations and invoke vast hysteria in others. Together, the Tengan eyes boost each others power while combining their abilities. The Tengan of the right eye is able to drag out a person's innermost fears and worst memories, while the left eye restores and intensifies the emotions attached to it, and in some cases, can even alter them altogether. The telepathic powers can manipulate the person's mind, causing them to see horrific visions of their past, while the empathic powers manipulate the person's emotional state exponentially, resulting in excessive panic.
The Tengan is not restricted to past memories. Users with adequate skill can create scenarios from their own imagination, almost akin to a Genjutsu. Unlike Genjutsu, however, the Tengan does not disrupt the flow of chakra, but the electricity and chemicals within a person's brain, and cannot be dispelled. This renders the Tengan almost unbeatable.