All for Nothing: Saint Germain dies never getting to fully be with his lover again.
Big Damn Heroes: Trevor and Sypha make their entrance with the Morningstar whip and a fireball respectively.
Big "NO!": Death lets this out when his plan to revive Dracula is destroyed by Trevor.
Canon Character All Along: Varney is not only the Alchemist who guided Saint Germain towards reviving Dracula, but is also Death.
Chekhov's Gun: The holy water and the spinning blade from Targoviste are used together to kill the Dracula/Lisa Rebis. The pieces of the sword that Trevor picked up in Targoviste are put together to kill Death.
Clock Tower: It's not a Castlevania final level if there isn't the clock tower. The party had to go through the last four vampires before they can stop Death's plan.
The image of Sypha appears for a split second as Trevor whips Death, showing that she's in his final thoughts.
There arrives the moment where it appears Trevor is disintegrating in the force of the explosion... but a viewer's eye can catch that he looks more sucked in rather than disintegrating. Come next episode, it's found the Infinite Corridor sucked him in.
Heroic Second Wind: Trevor, Sypha and Alucard teaming back up after being separated for two seasons gives them the boost they all needed to overcome their exhaustion and take down the vampire/night creature army.
Mercy Kill: Trevor finishing off Dracula/Lisa is this.
My God, What Have I Done?: Saint Germain seeing the horrific Dracula/Lisa monstrosity he sacrificed so much of his humanity and others is this for him. He even says it word for word.
Omnicidal Maniac: Death is this, wanting Dracula and Lisa to be revived in a hermaphrodite body so that their insanity will bring about the end of the world.
Opponent Switch: The heroic trio all find themselves in trouble or immobilized against the opponent they fight in the Clock Tower. Each one then decides to attack one of the other's opponent, successfully defeating each one and saving one another.
One-Winged Angel: Death becomes this after taking the power of the Infinite Key.