This monster appears to be the child of "Gishki Avance" and "Gishki Emilia"; this monster's hair is a layered combination of the white and red hair of "Avance" and "Emilia", respectively. He also has one blue eye (like "Avance") and one red eye (like "Emilia").
This makes sense, as "Avance" and "Emilia" were last seen in the conclusion of the Duel Terminal storyline (seen in "Sacred Serpent's Wake"), looking off into the distance together as the last survivors of the war. The duo are also featured on several other "Nekroz" cards, implying that the archetype represents the pair's new family after some time has passed.
"Nekroz of Brionac" and "Nekroz of Trishula" appear to be older versions of this monster. Their swords have similar designs and both bear the "Nekroz Mirror", as well as the same layered red and white hair (the helmet of "Brionac" would cover the white bangs of "Shurit"). They all also have the same red-green heterochromia– the same as "Shurit".