what causes Akoko to draw the battle line?

What chapter are you referring to? Owuor, who is deeply in love with his mikai refuses to take a second wife. The elders and the community are not pleased. Akoko is accused of juok (witchcraft) in the absence of her husband, Akoko is frustrated and goes back to her father’s house.

The fact that Akoko ,the wife to Chief Owuor is unable to bear more children and her husband is not willing to marry another wife, she is claimed to be a witchcrafe.She becomes hatred by her mother-in-law and brother -in -law ,thus she decides to go back to her matrimonial home and leave her paternal home hence decicive.