Gate to the Underworld
Yomutsu Hirasaka
rank: Connection, A+
A manifestation of Assassin's Authority as the goddess of the Underworld, this Noble phantasm turns the area surounding her into the slope that divides
central land of reed plains
Ashihara no Nakatsukuni
from
land of the dead
Yomi tsu kuni
. On this neutral ground between life and death, skills that depend on this diference are nullified.
She is also able to absorb things into the gate, sending them into the Underworld itself. Things inside the Underworld won't experience the pasage of time, so the state they enter will be the same as the state they come out regardless of when they are retrieved. Furthermore, Assassin can use this gate to "travel" from one place to another, taking advantage of the difference in time-space between the Underworld, achieving a result similar to taleportation.
Thousand Curses from the Goddess of the Underworld
Kegareki Yomotsu Ookami
rank: Anti-unit, Anti-Army, EX
Assassin's second Noble Phantasm, a always active power representing a physical manifestation of her curse upon the land of Living. It is actually supposed to be a Anti-country Noble Phantasm that starts an eternal cycle of creation and destruction, but a power that great cannot be supported in a normal holy grail war.
While someone simply looking at Assassin would only see a white and pure maiden, careful inspection would reveal a thin, almost imperceptible, veil of mist surrounding her at all moments. This is the "Fog of Yomi", a cloak of dirtness that hides her true form.
By calling the Noble Phantasm's name, Assassin can released the fog into the area around herself, rebeling her true form as that of a roting corpse, and inflicting everyone in it's reach with the greatest curse of all, the Curse of Death. Normal humans who enter in contact with this power will almost certantly die in a question of minutes, while Magus will probably resist for longer period of two to three hours. Servants will not die, but will be extremely weaken.
Beyond that, then curse will instal the concept of mortality in all of those who it affects it. Powers like Regeneration or forms immortality are completely nullified, and any unnatural forms of healing, be it through Magecraft or otherwise, have their strenght vastly reduced.