Date Kyosuke is a young man with problems. After being stabbed by his beloved mother, he discovers he has a long lost sister -- Runa. She is the first of many relatives that he and others in the story find tied into the seeming chaos of their lives. Date embarks on a quest to find Runa, aided by his new ability to turn into a monster; all the while in pitched battle at almost every turn with agents of mysterious organizations.
Unbeknownst to humans, demons from an overlapping dimension walk amongst them in the streets of Tokyo. The balance between the worlds is kept by the crow guardian Karas and Yurine, its master and voice of the living city. However, the time of harmony nears the end as the once-Karas Lord Eko returns. Seeking to purge humanity for its evils, he terrorizes the city with his minions that feast on human blood. The ultimate battle between good and evil awaits; can Yurine and her newly initiated Karas prevail against Lord Eko and protect their city against his monstrous horde?
Created by Tatsunoko Production at the turn of the 21st century, Soul Taker and Karas are dark spins to the superhero archetype fashioned by Tatsuo Yoshida in the 1970's. Karas has a lot more going in the eye candy department, but Akiyuki Shinbo's direction in Soul Taker makes up for it.
Kurahashi has never been the same since the hallucinations started. His condition is not medical in nature, and only seems to be triggered by an antique glass which shows him things he never would wish to see. For Kurahashi, figuring out the mystery of the Petit Cossette that appears to him in his waking dreams is a matter of life or death... and his sanity...
Both Petit Cossette and the Soultaker are directed and mostly thought up by Akiyuki Shinbo, and it shows. Shinbo's style is thickly laid over both, with tons of extreme imagery and symbolism featuring unique and complex scenes that suspend the viewer's belief and leave them on the edge of their seat.
The storyline in Petit Cossette is very similar to the Soultaker as well, almost as it were a miniaturized version of the story, but with enough differences in it's gothic style to keep it fresh and entertaining.
With a past shrouded in mystery and a blank memory, Shiki Tohno seems to be just another "average high school student". That is, until he nearly kills a female vampire with his secret deadly ability to "see the lines". His journey to unlock the secrets of the Tohno family and unbury his own lost memories has only just begun, and now he must also help the woman, Arcueid Brunestud, find a lethal phantom named Roa, and kill it using his ability.
The mischievous Komugi-chan is a cosplay idol and aspiring actress whose life is filled with adoring fans and jealous rivals. But secretly, Komugi-chan has a far more important and thankless job: a magical girl nurse who is tasked with saving the world! With the help of a magical syringe to fly on, an obligatory sidekick named Mugimaru and her Moe Moe Magical Shower special healing attack, Komugi-chan will overcome any obstacle... from mecha-anime cliches to viruses, to even death itself!
Surprisingly, these two series have one common link - Komugi. Yes, Komugi's first appearance took place in SoulTaker, and some people watched it just for her charming pink eyes. If you're one of these people, watch a whole series dedicated to your idol; or, if you want to learn her roots and see her in an unfamiliar light, watch SoulTaker. At least you'll get more Komugi.
Ryo Takatsuki injured his right arm in an accident years ago. The resulting surgery brought about some unexpected, but not entirely unwelcome changes -- enhanced healing along with the presence of a superweapon dubbed "ARMS" in his body. But with all power comes a price, and with newfound allies who share his predicament, he must battle a secret organization trying to control the ARMS while trying to find the truth behind the weapon in his body for himself...
SoulTaker reminds me of Project Arms to a degree. Mostly, the SoulTaker entity that the main character can transform into reminds me of Jabberwork from Project Arms. Add in some post/near-apocalyptic feel and a secret organization out to get the main character(s), and you have a firm basis for comparison.
I did feel that Project Arms had a better overall story however. If you enjoyed Soultaker, I recommend giving it a try. If you enjoyed Project Arms and don't mind a somewhat weaker series, feel free to give Soultaker a try.