Harm glyph doing straight physical damage and have nothing similar to potion of harm wich deals special magic damage - literally negative healing that magically damages living entities and heal undead.

Necromancy focus already enough effective, but there's lack of something... truly necrotic, negative.

Maybe it's time to add "true harm" somehow
Like glyph or even special glyph combo as bonus for wearing necromancy focus...
It could be combination with harm
or with healing...
Or even with both.

Knowing ars nouveau experience, I know
It's already too late to talk about balance
But
"true harm" wont do much here
Because not only
(In idea)
It could be obtained only in too late game
But even not effective much
Especially against undead, bosses... and undead bosses.

1)Self Phantom grasp doesn't drain hunger.