I'm hoping it's an evil race (I at least want one) that specializes in dark magic cursing enemies or spreading plague Necromancer poison specialists

A potential quest

you and your party are heading into town up ahead but in the last town you got a note telling you to infect the town or spread plague

So while in the last town you secretly released the curse /plague and its slowly killing the town your heading to
The last town your wizard got a quest telling him of dark wizards corrupting the local Lord so the town is already suspicious of wizard's

On the way you slip the plague vile into his inventory

The guards search him and arrest him and to make sure he won't mess with your plan's you enter the prison and kill him

Meanwhile your 2 other party members know your wizards been arrested so go to free him

So you have to stop it you tell the guards( you are in disguise )that your elf friend intends to free the prisoner he is arrested its up to your knight but now he has to deal with hoards of undead he goes to fight
But is outnumbered you as a fellow undead could save him but instead curse him weakening him greatly so he has to flee town

The Lord dies and you steal all the treasure and his magic book's before resurrecting your furious companions

They once again wonder why they brought you along