The lines,
"Marble-heavy, a bag full of God,
Ghastly statue with one gray toe"
as well as
"Daddy, I have had to kill you"
have a metaphorical meaning. "Marble-heavy [...] toe" refers to her father's time as a soldier. As her father was in the military she had difficulty finding a connection with him. "Ghastly statue", specifically, indicates that her father seemed emotionless and that she had difficulty, once again, caring about him because she did not know him. Finally, the author had to kill her father metaphorically because she never got to know him, and felt more comfortable burying his existence away from her in an act, perhaps, of shame for what he did or perhaps fear of recalling a fatherless, melancholy past.
You could say that tone is: patricide, coldness, distance, disconnection, isolation, etc.
