You’ve been imbued with the powers of the great imperial treasures, the sword Kusanagi no Tsurugi, the mirror Yata no Kagami, and the jewel Yasakani no Magatama each of which imbues you with a different power. Each of these effects can be applied to either your body, jutsu, weapons, or others but only one effect can be applied to one thing at a time but all three effects can be applied individually to different things. You can also choose to partially imbue something with an effect allowing the rest of it to be affected by another effect. i.e. you could imbue your body with Yata no Kagami except your arm which you could choose to imbue with Kusanagi no Tsurugi for example.
The Kusanagi no Tsurugi, grants anything you imbue the ability to kill anything with a single strike, from the smallest cut to the fatalist strike, from something as simple as a leaf to a bullet to a jutsu. Provided it hits what you intended it will kill.
The Yata no Kagami, grants anything you imbue the ability to be completely impervious to damage from something as blinding light to disease or aging. Nothing can harm what is protected by the mirror.
The Yasakani no Magatama, grants anything you imbue the ability to immediately and guarantee to travel and if you choose it, to hit it regardless of any defenses in its way. Although this does nothing for the durability of the thing your hitting, it merely ensures it will hit.