'Legacies': Dorian Williams may be more than just an innocent scholarly figure at this supernatural school
Before you dismiss this as a ridiculous theory, let's take a look at Dorian's history in 'The Vampire Diaries/The Originals' universe.
At first glance, Dorian Williams in 'Legacies' is like your garden variety school teacher working in a supernatural school. He's hard working, keeps a low profile, has not much to do with the curriculum and only shows up in odd hours when a monster needs to be put back into the ground. However, what if he is more than just an innocent scholarly figure? Before you dismiss this as a ridiculous theory, let's take a look at Dorian's history in 'The Vampire Diaries/The Originals' universe.
"Dorian Williams. I definitely remember you. What I did to you was so bad. Remind me what it was again -- so I'm forced to relive my guilt." pic.twitter.com/fbyLU7ZD90— TVD Writers (@TVDWriters) February 18, 2017
Played by actor Demetrius Bridges, Dorian was first introduced to us in the final season of 'The Vampire Diaries'. He was then very different from who he is now. The broody, quiet and observant, the Dorian you see now is a result of a tragedy. His recorded beginnings in the universe is when he came on Alaric Saltzman's radar and started interning in occult studies with Alaric and Peter Maxwell. He was a curious character - always trying to learn and understand the way of this world. However, his character arc takes a darker and more revengeful turn when he finds out what happened to his family.
Dorian's parents and sister had been killed in cold blood by Stefan Salvatore in 'The Vampire Diaries' during the span the younger Salvatore brother was trying to prove his loyalty to Original Klaus Mikaelson. He had to kill a lot of innocent lives just so Klaus could put his faith in him and it so happened that Dorian's family was one of his many victims. In 'The Vampire Diaries' when he kidnaps Stefan after the compulsion wears off, he demands an explanation and Stefan tells him what really happened - up until that point, Dorian had thought that his family had been killed in a huge fire that left him orphaned for life. The vengeance you see in young Dorian is fierce and unstable - almost as though he would pull the trigger at the slightest push. He's so upset by what happened, obviously, but what bothers him more was he had lived a lie. He does have the showdown with Stefan - but have you ever wondered if he could forgive Klaus for being a part of it?
Klaus was all too powerful for Dorian to touch, but his daughter Hope, who studies at the Salvatore School for the Young and the Gifted isn't really. She's one of the strongest witches, considering she's a Tribrid, but she is unsuspecting of him. She doesn't know that her father did what he did to Dorian's family. 'Legacies' may bring in an angle where they do have a confrontation but it's more likely that the hatred and pain may surface again.
'Malivore' showed us that Dorian is still very hurt by what happened - and he takes one day off in the entire school year just so he can spend time with his dead family on Remembrance Day. Come what may, that one day remains his personal time with Tina and Robert Williams. His anger too is quite evident when he snaps at Alaric on the phone. He confesses that on that one day he's unable to look at supernaturals the same way implying that he does harbor a certain dislike for them that can be potentially triggered on Remembrance Day.
In episode 4, 'Hope Is Not The Goal' things got a little suspicious. The spider-like monster that took the shape of a human being almost attacked him at the end of the episode. However, neither the episode nor the next one really talked about what happened - and there's only a passing mention of the incident in episode 5. Now, the spider-like monster could take human shapes - what if it took the shape of Dorian? Fan theories suggest that there's a chance that Dorian isn't Dorian anymore and that he did not talk about it in the fear of getting caught, obviously.
However, this wouldn't explain why he waited for The Necromancer to steal the knife if he had been employed to take it back to Malivore - but it is entirely possible that he's been planted at the school to keep an eye on Hope and Alaric. We know Hope will definitely be crucial in the destruction of Malivore and he could be there to manipulate her. Remember in episode 7, 'Death Keeps Knocking On My Door' he gave Hope the books she was supposed to give Alaric. Instead of going to Alaric, Hope went to the dungeon - it wouldn't be too far fetched to say that Dorian knew where Alaric was and sent Hope there because he knew what would happen.
Even if they make him out to be a monster, it would definitely add a great character twist to Dorian.