Build a charger; 2h chargers can possibly 1hit-kill many characters; although I would think about perhaps making one with a shield because other people will probably bring their own (eth bonesnap?) chargers.
Although in my opinion charge vs charge is mostly about luck anyway...
Not sure if the rules allow it, but you can also heal with the auras.

In classic bone necros can stop chargers with well placed bone walls, not sure if this is allowed in your tourney.