minecraft-expanded-datapack/assets/undeadm-m1/models/item/melee_weapon/diamond_halbard_b.json

{
  "parent": "undeadm-m1:item/base_weapon_halbard",
	"textures": {
		"layer0": "undeadm-m1:item/melee_weapon/diamond_halbard_b"
	}
}