Begin with fibrous green rectangles, seal the deal with skin, bruises, and blood

The dark gods heard my piteous cries and accepted the meager sacrifice I cut from my bank account.  In a matter of days, my fate was sealed.

I was unprepared for the hidden claws in the devil's bargain.  This demon weapon is driven by an insatiable thirst for metal and blood.  Should you neglect to feed it the first, it will take the second the moment your attention drifts and you fail to bind the demon to your will.  But dear god, does this thing rule.