We don’t what he was holding when he went into bankai in ep 5 because they didn’t show us all we heard him say was bankai and he came out of the darkness and his two swords were one! Half black and white like how his powers always been …. Also he still had his horn of salvation out before yhwach destroyed his bankai and based off episode 5 the blood chains is the form he takes when he enters bankai with his horn of salvation!