Here is an idea whether AN can work it into the traits is unknown.
I wish there was a trait that would pop like retaliation does but with a twist.
I call it virulence.
When it is active anything within close contact hitting the necro will pick up conditions like plague form. Have it potent within a radius but easily countered by ranged attacks. Melee will have to refrain from attacks on the necro or get conditions for each attack. Ranged will have to judge whether or not to attack the necro while their melee friends are near the necro in a virulent state or risk giving conditions to their team.