Hisa Masato manga
Shio Ogura is a Japanese high school student, who is visiting Taiwan on a school trip when she is suddenly attacked by monsters. Agents known as "E-Gene Holders" from the government agency DOGOO also arrive, who wield weapons infused with the spirits of historical figures. Shio is revealed to also be an E-Gene Holder when the soul of Oda Nobunaga awakens after she tries to rescue a friend.
One of the Japanese promos calls it "Da Vinci Code meets Jurassic Park". I think that sums it up pretty nicely. It's got dinosaurs, spies, intrigue, action, and conspiracy, all rendered in lovely film noir-esque art with a little fan service cherry on top (Lily!). And for the slightly geeky, it's got cool (and sometimes obscure) references to art, literature, film, history, science... you name it. Definitely a manga for adults!