Dead Cells Castlevania DLC - Alucard's Sword and Shield Interaction

Equipping both Alucard's Sword and Alucard's Shield upgrades the moveset of both - the sword gets shield parries between attacks; The shield can crit after landning a hit with the sword.
You can get the shield in Castle's Outskirts lore room where you awaken Alucard, and the sword from the hidden Richter mode.
Alucard skin not necessary.