Alivened
An Alivened is a type of Golem created by Dark Oculators.[1] The most powerful ones are referred to as Codexians and are made of paper. They can manipulate the mass of their bodies, regenerating limbs. This does cause them to shrink in size. They are relatively fire resistant, and extremely strong.
Alivened are created by Dark Oculators(a branch of the evil Librarians who secretly rules the world)who give up some of their humanity and invest it in the object to be Alivened. This removes some of the good human qualities from the Dark Oculator, but the Alivened object does not retain these good qualities -- they are twisted and evil instead. Codexians are made out of bad romance novels because they can soak up emotion, making them especially powerful.[2] They guarded the library that held the Sands of Rashid.
They also helped Alcatraz discover an important part of the book that we won't spoil for you.
Members of the sect of librarians called the Scrivener's Bones have a penchant for replacing some of their body parts with alivened parts. A notable example of this is Kilimanjaro, the main antagonist in the second book of the series, who replaced a full half of his body with alivened metal. This sect sees not only the stronger material as an advantage, but the removal of humanity as well.