Hithpaelim

Hithpaelim, or Niphalim (not to be confused with Nephilim) are Keruvim who, through abandoning themselves to a sinful life, or through the use of Artifacts or Nephilimic Runes, have dropped out of grace (similar to the fall of the angels). Their name means "Forgotten Ones." It is important to note that when the term "Keruvim" is used it often refers to both keruvim and hithpaelim.

Nature
Hithpaelim who return to the cause of God are never returned to their original state, but are still able to enter Heaven if they are devout in their ways. Hithpaelim also lose the privilege of having an angelic partner.

Hithpaelim can reproduce with keruvim to produce keruvim; Hithpaelim are created through a choice and are never born into that state.

Angelcy
Hithpaelic have the same abilities as keruvim, thought they are slightly dampened unless constantly practiced, and spiritual Sight fades from distinct sight to vague forms of spirits, much like Nafwl Sight. The two other differences are that their wings go from white to grey and lose their light during manifestations;

and that Hithpaelim have hollow eyes, like the Unliving (thought the sclera is still white, unlike the Unliving, who have darkened scleras).