A Weapon is usually a type of harmful object in order to kill someone or physically and emotionally hurt a victim, which could result in their death. Below is a list of weapons in order to kill a particular species.
A wooden stake of any kind and type is harmful and also fatal to a typical vampire. From wooden pencils to tree branches, a wooden stake through the heart will permanently kill them. Often, getting injured by wood weakens vampires to the point where they seemingly lose all their strength and ferocity, enough for even mere mortals to overpower them. Alaric and John both own a gun which shoots them presumably made by them as well, respectively. Logan Fell also owned a hand gun filled with wooden bullets.
Werewolf venom can be extracted to further enhance the lethality of wooden stakes.
In order to heal the wound, the substance must first be removed to allow the vampire to recuperate. It depends how old a vampire is - the older the vampire, the faster the wound heals. It also depends on whether or not the vampire feeds on human blood, as well as how often they do. Therefore, a vampire that is older and feeds on human blood regularly would heal faster than a young vampire who rarely feeds on human blood. If a vampire has access to a blood source, they will quickly be able to heal from any non-fatal wounds.
The darts contain a liquid infusion of a herb called vervain, which can severely weaken typical vampires, and sometimes, in large enough doses, or with severe skin exposure to large amounts, vampires can be weakened to the point of death. Some of the tomb vampires were killed or weakened to the point that they could easily be killed using such darts, during a fight in the house of Samantha Gibbons, where the vampires had compelled her to allow them houseroom and permission to feed on her. Most of the darts were made by Alaric Saltzman and can be shot from the same gun that shoots wooden stakes. Elena also stabbed a dart into Stefan and Frederick, at two different points, in order to weaken them. They are usually kept in a silver dart with a long point in order for the vampire to be hit with it. When hit, the vampire will instantly be injected with the vervain infusion, and if they do not have a tolerance to the herb, they will usually be weakened or incapacitated within seconds.
Vervain Grenades
The vervain bomb was designed again, by Alaric Saltzman, using a glass jar filled with the same liquid vervain infusion used in the darts, attached to a blasting cap. When detonated, the glass shatters, cutting whoever is nearby with broken glass and exposing them to a mist of vervain water. Elena used it against Elijah when she was kidnapped by Rose and Trevor. Elijah, an Original vampire, arrived to claim Elena in order to break the curse. However, she pulled the vervain grenade out and threw it at him. Vervain burns vampires, and immediately following the throwing of the grenade, Elijah began to burn. The usage of a vervain grenade has not shown on a regular vampire, however, it can be assumed that using a vervain grenade on a vampire will affect the vampire more than it would affect an Original vampire.
The device was created by Johnathan Gilbert and was later spelled by Emily Bennett in order for it to actually work the way he intended. When activated, it lets off a high pitch frequency for five minutes within a five block radius, causing all of the vampires (and werewolves)with that radius to become exposed. The noise registers at a level that only someone with supernaturally enhanced hearing can hear, and incapacitates them enough so that the vampires can be injected with vervain to weaken them further, before killing them. The device nearly got Damon and Stefan killed, but they were saved at the last moment by Stefan and Alaric, respectively. However, it did kill most of the tomb vampires when it went off, as well as Jeremy's girlfriend, Anna. The vampires were injected with vervain and dragged into Grayson Gilbert 's old medical practice, where they were doused in gasoline and left to burn alive, though John Gilbert did stake Anna before lighting the fire. Jeremy was so distraught by her death that he ultimately drank the vial of Anna's blood that she had given him, and tried to overdose on painkillers to turn into a vampire so he wouldn't have to be sad about her death.
Werewolves
Gilbert Device
The device also works on werewolves as well, even those who have yet to trigger their curse. Unknowingly, when the device was activated, it caused Richard Lockwood and his son, Tyler Lockwood to hear the noise. Richard was the first to be seen to pass out, though it appeared that he didn't actually hear the noise. Still, the deputies assumed he was a vampire, and injected him with vervain before taking him to the medical building with the other vampires. Tyler was also affected while driving Caroline and Matt home. The noises started to affect him, however they were more than five blocks away, hinting that werewolves have better hearing than vampires. He suddenly got a migraine as a result of the noise, and the pain was so unbearable he let go of the steering wheel to clutch his head, which ultimately caused the car to crash into a wall.
This device was designed by Alaric Saltzman, he used a glass jar filled with Wolfsbane that's attached to a blasting cap. Once detonated, the glass will shatter, cutting whoever is nearby with broken glass and exposing them to a mist of wolfsbane water. It was used a second time by Katherine Pierce, she was at the Lockwood Mansion, surrounded by Hybrids, so she tossed them up in the air, they detonated and burned the hybrids.
One way to neutralize an Original vampire is to stab them in the heart with a dagger coated in the ash of the ancient white oak tree from which the Original vampires were created. Once stabbed with the dagger, the Original desiccates and is sent into a death-like sleep until the dagger is removed. However, if you take the dagger out of the body, even just once, the once-neutralized Original will be revived. It's not like a wooden stake in the heart for a vampire, which is instantly fatal, regardless of whether the stake is removed.
The only way to kill an Original vampire permanently is to stab them through the heart using a stake that was carved from the ancient white oak tree that was used in the spell to create the Originals. However, unlike other stakes and the silver daggers, once this stake is used to kill an Original, it bursts into flames along with the Original's body. At first, the only known stake was destroyed when it was used by Klaus to kill Mikael. It was revealed in the episode All My Children that a sapling of the white oak tree grew 300 years after the Original family left, and the Mystic Falls gang eventually made a dozen stakes in an attempt to kill the Originals. All but one of the stakes made by Stefan, Damon, and Alaric were destroyed.
The Indestructible White Oak Stake
After the losing and demolishing all other white oak stakes, Alaric's vampire-hating alter-ego hid his own white oak stake in the Lockwood's secret cave, where vampires are magically unable to enter. Then, after meeting with Esther, she convinced him to sacrifice his Gilbert ring in order to unite its protective magic with the stake, which would prevent the stake from being destroyed after it was used. Using her magic, she melted the ring and dipped the stake into the metal, creating a protective metal coating around the entirety of the wood. The stake was first used by the Alaric shortly after being turned into an Enhanced Original by Esther. Alaric used it in an attempt to kill Klaus, not knowing that Bonnie saved him by moving his essence into Tyler's body. Then, it was used by Jeremy after he was activated as one of the Five. Kol tried to kill Elena and attempted to cut off Jeremy's arm, so Jeremy and Elena were forced to work together to kill him, both in order to protect themselves, as well as in the hope that the deaths of Kol's entire bloodline would complete Jeremy's hunter's mark and lead them to the cure. On the island where Silas was entombed, Elena gave the stake to Rebekah as a peace offering, after Rebekah saved her life by protecting her from a trap. Later, Elijah took the stake from Rebekah and gave it to Klaus, as a way to assure him that it couldn't be used against him, in return for giving the cure to Rebekah. Klaus was last seen using it to threaten Rebekah in the series The Originals.
A knife, is usually a sharp steel object using for cutting mostly food, however it has been used to kill someone or to wound someone enough to send them a message. Katherine pretended to be Elena in order to gain access to the Gilbert House. Once she did, she continued to pretend as she talked to John Gilbert, and eventually cut off the fingers on his right hand with a butcher knife before stabbing him in the stomach with it. After Katherine got into the Gilbert House, she switched Jenna's vervain perfume with a regular one so that she could compel Jenne to be her spy. Unknown to Elena or Alaric, Katherine had compelled Jenna to stab herself in the stomach as punishment for Elena not following Katherine's rules. Thankfully, Jenna was taken to the hospital just in time, and quickly recovered. Elena also stabbed herself with one of the Originals daggers, to scare Elijah into making a new deal with her, since he needed her alive in order to break the curse.
Bullets
Bullets are normally shot from a from a hand gun or a rifle of some sort. It was shown that they have little effect on vampires or werewolves, aside from the inconvenience of having to heal. However, it can easily kill a human being without any supernatural powers. The overall most notable time this had happened, was when Jeremy was attempting to help Damon to the Mystic Grill in order to call for help. However, he didn't hear Liz Forbes walk in with a hand gun. She attempted to shoot at Damon, but he quickly sped away, causing Liz to accidentally shot Jeremy in the heart, killing him. Thankfully, Bonnie was able to do a spell, with the help of the spirits, to bring him back to life.
Illness and other medical factors can also harm/kill a human.
Cross Bow
Crossbows are weapons commonly used by vampire hunters. They are quiet and accurate, being able to almost silently catch a vampire offguard. Though not shown to be able to kill a vampire, unless they're wooden, an arrow fired from crossbow has been shown to hurt them and at least buy the hunter some time.
Usage
Crossbows have been used by a number of vampire hunters:
Kept crossbows hidden with the rest of his vampire slaying weapons in the drawers of his apartment. Some of his crossbows were used by Mystic Falls students that Klaus had compelled during the 60's Decade Dance.
Brought a crossbow with him for protection when traveling with Elena to a werewolf pack's camp.
Trained and practiced with a crossbow prior to becoming a member of The Five. He'd shoot cans out in the woods with Tyler.
Shot the hybrid, Tony, in the back with an arrow, which gave him enough time to finish him off via decapitation.
Once a member of The Five, he wielded a crossbow when he was preparing to kill that vampires that Klaus had forced making and was ready to use it on the Original, Kol, when he discovered that Kol had already killed these vampires.
Vaughn used his crossbow as a surprise attack from hidden locations. He shot Damon with an arrow before ambushing and capturing him.
He used his crossbow again when he tried to shoot Damon again from afar after Silas had awoken. Damon, who was walking with Rebekah, used her as a meat shield before Vaughn fired another arrow, which Damon caught before pursuing the hunter.
Stefan Salvatore
During vampire defense training with Elena. He shot a arrow at her so she could practice dodging it.
Hybrids
Vervain or Wolfsbane-Grenades
Being half-vampire and half-werewolf, hybrids are affected by both vervain and wolfsbane. As the hybrids attempted to save their master Klaus, who was close to be killed by Damon, Katherine threw wolfsbane grenades (which were invented by Alaric Saltzman) at them. It hurt them to the point that they stayed away, but it didn't kill them, as Mindy and Tony were still alive after the party.
Supernatural Hunters
The weapons of The Five bear a distinctive mark, that is very similar to Vegvísir, but distinct, as the Vegvísir has 8 arms, while the Hunter's mark has 6.
