or twinborn allomantic and feruchemical nicrosil, allowing you to compound investiture and wield nightblood for as long as you desire, also a-atium and f-speed to help avoid being hit, a-pewter to help break through the shardplate, and f-gold in case he manages to hit you although since you have atium you could probably replace it with a-chromium to wipe out his stormlight or a-steel to help move around