Mangekyou: When a wielder of this ocular ability experiences a powerful emotional condition with regards to a person precious to them, their brain releases a special form of chemical that affects the optic nerves, transforming the eyes into Mangekyou; for that reason the Mangekyou is described as an "eye that reflects the heart". Often, as per the Akaru's so-called "Curse of Hatred", this emotion is a negative one, brought on by stress or loss. The emotion can also be positive, driven by a desire to protect or reunite with a loved one.
Dōsatsugan (Eye of Insight) - The user can see the "fighting prowess" of another, giving it color in order to distinguish it by its composition and source. It can see this aura through some (but not all) obstructions and detect irregularities in a person's energies, such as those caused by illusory influence. The user is granted incredible clarity of perception, enabling them to read lips or mimic something like pencil movements. Sanosuke's eye is even able to see on a cellular level. In combat, this allows them to see fast-moving objects and, once fully developed, offers some amount of predictive capabilities: they can anticipate an opponent's next move based on the slightest muscle tension in their body and act accordingly to dodge or intercept. With advanced enough prowess, via eye contact, the user can even enter target's mind to look through their memories.
Saimingan (Eye of Hypnotism) - While there are various manifestations and purposes of the ability, the better known one is to, through eye contact, suggest thoughts and actions to a target, coercing them to divulge information or act in a particular way, potentially without the target's awareness. In extreme cases, the Mangekyou user can take complete control of the target's body, forcing them to do exactly as the controller wishes; this control is visually indicated by the Mangekyou's design appearing in the target's eye. Multiple targets can be taken control of in this way, though the more divided the user's attention is, the easier it is for targets to escape this control. While not an ability per se, the user can appear as if they are able to "see the future". First, the user must perfectly mimic every move their opponent makes and possibly their thoughts and words through careful observation. Then, they suggest an action to the opponent such as a technique that the opponent and user already know and copy that. With these things done, the user can complete the action even before the opponent does, possibly using illusions to confuse or delay them.
