best curse for a summoner

What's is the best curse that I can use to amp up the effect of my minions physical damage and my spell (lightning) damage?

Vulnerability for physical damage.

If I were you, I'd go with wrath and/or anger and get another curse, say, elemental weakness (for wrath AND anger), flammability (for anger) or conductivity (for wrath).
Altho flammability for anger is pretty worthless, since burn damage is gonna be weak. :-V

Enfeeble/Temporal chains are pretty solid in ever case.