Yin Seal of Divine Protection

Yin Seal of Divine Protection (天佑の陰封印, Tenyuu no Infuuin) is a special seal designed by Saizen. This seal gives Saizen fortification against most attacks. It's based on spiritual energy, otherwise referred to as "Yin". The seal is placed on his right eye, which is concealed by his eyepatch. The seal is filled with a great portion of Saizen's Yin energy, which contains his will. As soon as Saizen sees an incoming attack, the Yin energy circulates in the mind, then transfers to the nervous system, which contains Saizen's Yin energy in it. When Saizen sees an attack, his will would be directed to protecting himself. As Yin energy contains Saizen's will, it will send a command to the nervous system, which says "protect me". At that moment, the seal will activate, moulding Saizen's chakra and executing defensive techniques in order to protect him instantly.

The main advantage of the seal is that it provides instantaneous protection, as it activates as soon as Saizen realizes there's an incoming attack. The seal does the rest as it moulds his chakra and protects him in an instant. Thus, this seal forms Saizen's "Automatic Defense"

Trivia

 * Saizen often refers to the seal as "Tenyuu"