Zenshagan

Zenshagan (前者眼, Past in Time Eye) is a that has appeared sporadically throughout the ancestry of the Daimyo, appearing the most during the Warring States Period.

Overview
Unique among doujutsus, the user cannot perceive chakra or the chakra pathway system of a shinobi. Instead the eye allows the user to access the fabric of time, in this case the past. With it, they can review past events that have gone on throughout the ages. How it works is partially based on where the person is currently located. Once the person has activated their Zenshagan, their soul is separated from their body and taken back in time to the events that have occurred in the specific area they are in, including battles, treaties, etc. Also, The user can than sort through events by specifying what time period, date, or event they are looking for.However, this ability requires the user to already have some knowledge of what they are looking for. Those who have more powerful eyes are said to be able to reach beyond a few simple years, and have the potential to view many or even all the ages past. This is a rare occurrence however, one that has been said to have only happened twice in the doujutsu's history. Lastly, the user cannot interact with these events for they have been already decided. In other words, the user is a bystander that is simply watching the comings and goings of what has already happened.

Weaknesses
The itself can only be utilized a few times a day, as each time the user "visits" the past, they surrender a small piece of their own past. The more its used, the more the user forgets their origins. While these forgotten memories can come back with time, if the user goes over the threshold, those memories could be lost permanently. Also, though the user is traveling through time to see the past events unfold, their physical body stays behind in the present. Therefore, it is necessary that the user hides their body or has bodyguards with them, or else they would be vulnerable to attacks. Should the user's body be destroyed in the present while their soul is visiting the past, the user could be left in limbo.