Ranmaru's kekkei genkai

From Narutopedia

Ranmaru has a Dōjutsu Kekkei Genkai ability similar to the Byakugan. It includes penetrating vision, disrupting eye-based kekkei genkai, and a unique chakra particle extension. He had the ability to use his vision abilities to penetrate the walls of his small shack and view the outside world and perform Genjutsu that can fool even the Byakugan. This ability does not appear to have the range of the Byakugan, but it actually has the ability to counter that Hyuga trait. Ranmaru's vision is also able to locate and track others by sensing chakra, pick up chakra from long distances, and notice changes in an individual's chakra. It is also able to sense how many of them are present.

Ranmaru's vision has heightened perception and analytical powers not unlike the Sharingan, meaning Ranmaru can comprehend any details he sees to predict the opponent's next move. This ability contributed mainly to Raiga being so formidable in battle and becoming one of the Seven Swordsmen of the Mist. He can also see one's life force, allowing him to determine that Raiga, who had recently fallen in battle, was still alive,and he was able to transfer part of his own life force to Raiga. When activated, Ranmaru's eyes momentarily glow red.