"Because I hate him," Iago's answer is simple, plain, without hesitation, and punctuated with a nosebleed and a bright flash of pain behind their eyes like a hot knife. He always ensures their blasphemy comes with punishment.
They worry the blood is too enticing, that they shouldn't be such a tease when one of their kin is so close, but it's dribbling down their chin, now, staining their collar. Iago moves further back in the dirt, feeling tiny beneath her but going on anyway. They only ever dig their own grave deeper.
"I hate him," Iago spits, wiping at the red trickle on their lip. "More than anything. I hate him and every ounce of blood in me that he can claim." They want to kill him, but they can't, so they can at least find satisfaction in keeping his favorite toys away from him.
"And you- Nan, you're someone. I've spoken to you more in this short time than I have in all the years I've known you. You're alive, out here, you're- you're real, do you understand?" They aren't sure they're making any sense. They're feeling a bit dizzy while the words spill out of them, "He will never be happy. He doesn't want any of us, he wants a doll, disposable and replaceable when it breaks. At least this way, here- You- We can be someone for a little longer."
She looms down closer and they feel their heart jump. There is a well-deserved hatred in her eyes, but her voice is small. Hurt. Iago briefly considers offering up their braid for her to strangle them with.
"I was afraid," Iago answers her, barely a squeak.
And therein lies the monster Bhaal made of this one. Their kin, he forged into weapons sustained only by never-ending slaughter, bathing them in blood and gore. Iago, he designated fodder from birth, filling their tiny heart with fear until there was nothing left. Their monstrosity is not a flashy, tangible thing of violent outbursts and gnawing hunger. Rather, it is the ugly, overstayed survival of a weak, defenseless thing left with only cheap moves and cruel games. But it is a creature of Bhaal's making much the same.
"Then somewhere along the line, it became easier. To care, I mean. Not just to pretend, but to really... feel something. About you. And the others. And strangers, even, whom I've never even bothered to pretend for, really, but find myself thinking about them so much more these days-" Rambling. "I am not a good person, Nan, but I- I like the person I'm trying to become."
Their next words come after a pause and are nearing a hysteric sort of amusement at their own wreckage, "And I've done such a poor job thus far that I have no doubt you'll think that another lie! I know I would."
They hope she breaks a bone or two. It might make them both feel better.