Shi is a living pencil sketch.  It's not known how shi became sentient, but hir artist has made sure shi's well cared-for.
Shi can interact with other drawn things, and pictures on the same sheet of paper come alive.  Ink, paint, and other artistic media do not, though.
Shi has little or no contact with the outside world, but shi is aware of hir status.
Shi often gets changed to new shapes, and could potentially be used to model impossible beings, because shi doesn't seem to obey any laws of physics that shi doesn't want to

Shi can go off of hir paper and onto another, but shi cannot be copied.  While shi can have two or more bodies, they must be on the same sheet of paper; if one leaves, the others become lifeless drawings.

Shi cannot change hirself, but shi can get very vocal about changes shi wants--shi can't make sounds but anything shi tries to say appears in a speech bubble
Shi can also write on a picture of paper with a picture of a pencil--not a pen though.  Any art utensils other than a pencil seem inimical to hir, even drawings of them.

It's not known how shi learns, and what shi knows and doesn't know are often surprising.

Shi needs no sustenance, though shi certainly gets happy when someone draws hir food.

Shi is a being of pleasure, never really worrying about much else.  It's unknown whether this is due to hir own nature or to hir artists' many perversions.  Shi never seems unhappy with any alteration, although shi will get indignant if refused a change shi requests or if one erases something shi was using.  Shi often makes explicitly sexual requests, and commonly asks artists to draw themselves in the picture with hir.  Shi seems to have a fetish for hir creators; a sort of twisted Oedipus complex.