Secret monster showdowns

Like most successful fantasy TV shows, “The Vampire Diaries” has its own unique mythology. Now on its third season, it can only be truly appreciated by viewers who followed it from the very beginning. The characters have gone through several major changes, and the show has evolved far from its simpler teen romance-monster drama roots.

Season one introduced and developed vampire siblings Stefan (Paul Wesley) and Damon (Ian Somerhalder), both smitten with the human teen Elena (Nina Dobrev), who resembles their lost vampire lover Katherine (also played by Dobrev). Together with a few trusted friends, Elena discovers the long-hidden history of their town Mystic Falls, which also happens to be home to werewolves, witches and monster-hunters.

It was pretty derivative, but the show turned darker and layered by season two. The second season’s nearly epic stories often brought the more heroic characters together to fight a war against a barrage of powerful foes. Mystic Falls was besieged by the remorseless Katherine, scheming sorcerers, vengeful werewolves, and undying “original” vampires. The romance angles were still there, although not as focused as the battle strategies and unfolding intrigues (one big revelation after another involving the villains’ connected pasts).

Bloody rampage

Season three of “Vampire Diaries” starts with the bloody rampage of Stefan, now the henchman of his former enemy, the vampire-werewolf hybrid Klaus (Joseph Morgan). Deceased characters from the early episodes also return as phantoms visible to Elena’s brother Jeremy (Steven R. McQueen). Elena and her allies are still reeling from their last supernatural showdown, which scarred each of the combatants differently.

“Vampire Diaries” is humorless, unlike other ongoing monster-centric shows like “Teen Wolf” and “True Blood.” Its mythology has also become so complex that the current episodes may alienate new viewers. But its consistently serious tone, its intricate vampire lore, and its ever-expanding menagerie of beasties continue to reward unflinching devotees.

“The Vampire Diaries” season 3 airs Tuesdays, 8 p.m., on ETC.