"In the midst of a heated battle, just as Nasus was about to slay his treacherous brother Renekton"
" Consumed by his anger, Renekton turned on the one being who could defeat him -- his own brother. Nasus pleaded with Renekton to see reason. Realizing that he was beyond redemption, the despondent Nasus valiantly struck down his wayward sibling. Defenseless, Renekton waited eagerly for death's release. It never came.
Someone tell me I'm retarded and I'm reading this wrong. The lore seems different on when/how/where Nasus was about to kill Renekton
Edit: Put in more of the lore from renekton's side.