At the most basic level, they differ in terms of what they are analyzing. We'll work with your example (in part): It is wrong to kill someone.
A consequentialist theory tells you something is right or wrong based on either the intended or actual consequences. In its classical Utilitarian articulation, it also include a "harm principle" that prohibits harming others in the process of maximizing pleasure. But this harm principle is not justified in terms of maximization -- thus showing one potential problem for these theories. Looking at it "it is wrong to kill someone," the consequentialist says this when there is a negative consequence relative to the valuable commodity lost in killing someone. On such an account, it is conceivable that killing someone could be not merely licensed but morally praiseworthy or possibly even obligatory.
A deontological theory says actions are right or wrong based on whether or not they express the completion of duties or not. Looking at "it is wrong to kill someone," the deontologist tells us that it is wrong because killing someone violates a duty -- either to oneself or to others (possibly including God). On such an account, if killing is wrong as a violation of a fundamental duty, it is always wrong. (It could also be wrong on more contingent grounds -- I promised not to kill you until next week Tuesday so I have a duty to my word and to your promise).
A virtue account generally asks whether they allow the person to flourish and grow. Here, the virtue account tells us it is wrong to kill someone because of how this warps the character of the person and how it fails to demonstrate excellence in response to one's emotions or thoughts. There's a lot of different virtue theories so it's going to be hard to nail down what "virtue theory" says as to when/why it's wrong to kill someone.
Given these basic sketches, one could see virtue accounts a species of consequentialism centered on a certain idea of the person and its excellence. It's going to be much harder to draw deontology into a consequentialism but it can be done by suggesting that what we are maximizing is the completion of duty. But it won't be identical because you're still evaluating differently when looking at the morality of actions.