Fellow manga readers I need your help. I you can plainly see I have a list. I have an unhealthy obsession with monsters struggling to be human, and/or humans becoming monsters themselves.

I'm going to use Toukyou Kushu as my case example, since humans being overcome by their monster counterparts is my favorite, but since I like all sorts of monster stories I want to leave it open. (I read Kamisama Kiss which is about as far away from Toukyou Kushu as you can get)

The only thing I'm not looking for is where all the monsters are evil. Think classic zombie apocalypse. If there's say, some half-zombie protagonist or something, I"m all in, but otherwise not my cup of tea.

But really I'm having trouble finding new reading material, help me please!

Also, for the sake of people with the same interests, I categorized my monster reading list, and bolded anything I'd recommend reading. A + symbol is for any completed series. (I may have misrepresented a few though, so forgive any errors) Some of them are also not currently updating with translations but I listed them anyway... sorry about that too.

the monster is you

Cyborgs/robots
Hitogatana
Classmate, Kamimura Yuuka wa Kou Itta
+Cyborg 009

Demons
Aflame Inferno
Antimagia
Blue Exorcist
Devilman
Goumaden Shutendouji
Nora
Nurarihyon no Mago
Sengoku Youko

Undead
+3x3 eyes (and also demons)
Boku to Majo no Jikan
Immortal Regis and it's sequel Cavalier of the Abyss (also demons)
Itsuka Tenma no Kuro Usagi (also vampires)
Princess Resurrection (vampires, werewolves and other monsters)
Sankarea
Shindere Shoujo to Kodoku na Shinigami

Vampires
Dance in the Vampire Bund (also werewolves)
+Darren Shan
+Hellsing
Pureblood+Boyfriend
Rosario + Vampire and Rosario + Vampire Season II (also a cast of other monsters)
+Rustblaster

Monster
Cerberus (Gravekeeper dog)
+Kurozakuro (Ogre)
Ryuu wa Tasogare no Yume o Miru (Dragon)
Toukyou Kushu (Ghoul)
Undead (TERASHIMA Masashi) (monster undead?)
Verdant Lord (trees)
+Blue Dragon: Ral Ω Grado (Dragon/shadow)
+Yoru to Yakusoku (werewolf)

Weirdness
Chronos - Deep (shadows)
D. Gray-Man (Innocence? and other shenanigans)
Death Edge (I think they're vampires... or demons or angels. It's not clear)
Dogs Bullets & Carnage (experimentation/ alternate personality)
+Inugami (dogs)
+Parasyte (alien parasites)
+Shingetsutan Tsukihime
+Specter (parasites)
World Embryo (aliens technically)

Monsters are good
I separated these ones because they also have monsters, but the struggle for humanity against the monster is less at play, and it's more about their strangeness or otherness that's played upon.

Akuma to Dolce (demon)
Ansatsu Kyoushitsu (alien/experiment?)
Beelzebub (Demon)
Black Butler (Demon)
Blood Lad (Vampire)
+Bloody Kiss (Vampire)
Choujin Gakuen (human, demon, everything)
+Fullmetal Alchemist (this probably doesn't count, but homunculus)
Kamisama Kiss (Fox demon)
Karakuri Odette (robot)
Yumekui Merry (nightmares)
Zombie Romanticism (undead duh.)

Black Rock Shooter - Innocent Soul (sort of)
Dawn - Tsumetai Te
Donten ni Warau
Ryuu wa Tasogare no Yume o Miru
Tokage (again, sort of)
Tousei Gensou Hakubutsushi (sort of)
Vampir
Variante
Yoru no Kakaku

And maybeee Arago. It's kind of a stretch, but it could fit.

Also, Franken Fran has a lot of humans-becoming-"monsters" but it's mostly for satirical/social commentary purposes.

the second part of sengoku youko

Sugar Dark?
Zetman?

Also, Go Go! Pudding Empire.

Since you listed also cyborg/robots, I'd suggest to check Pluto (can robots go against The Three Laws of Robotics?), Gunslinger Girl (are female cyborg assassins still normal girls?) and Kurogane (can a cyborg still love?).
Not listed but imho relevant, mutants: Elfen Lied.

What I like in Trivial Pursuit style. Pick your category:[img]http://i379.photobucket.com/albums/oo233/Reid4891/Manga/trivia-1.jpg[/img]

Thanks a lot guys.

I'd completely forgotten I'd read Sugar Dark before. Very good.

I read too much of Franken Fran in one go and haven't got back to reading the rest of it. It's kind of intensely grotesque.

I'm also a big fan of close enough. Series that are kind of close to what I'm looking for tend to be just as interesting as those that match up.

I'm going to slowly mosey through everything here, so thanks for helping me out!