Arrow: 8 Best Villains

Unlike Malcolm Merlyn in the show's first season and Deathstroke in its second, Ra's al Ghul, the infamous leader of the League of Assassins, pretty much succeeded in killing Oliver Queen halfway through season three. After stabbing Oliver, ending a duel between the two men, and kicking his body over a cliff, Ra's walked away having proven himself quite the badass, though Oliver ultimately survived due to the cold slowing his blood loss while rendering him unconscious long enough for Maseo to recover his body and give Tatsu the chance to revive him.

Oliver's survival earned Ra's respect and renewed desire to have the vigilante take his place as the Head of the Demon in the season's second half, something Oliver used against him by joining the League with the intention to betray him, but ultimately Ra's himself never quite reached the heights he did in the first half. His plan to destroy the city and inevitable defeat at the hands of Oliver played out rather predictably, which only served to turn a unique, dangerous villain into a pretty standard threat by season's end.

Though he exited with more of a whimper than the bang he deserved, Ra's legacy continued to be felt - and still is - in the seasons that followed, his absence creating the power vacuum that Nyssa and Merlyn fought to fill, opening the door for Talia's eventual emergence on the show, and changing Oliver and his outlook on life, for better or worse.