Hybrid Theories

[JustAGuy]

I also had maxed Cold Mastery and found that it does not break immunes. Conviction does and so does Lower Resist. Think about it, if Cold Mastery could break immunity why would anyone play a fire sorc?

Correct, Cold Mastery does not break immunes. Conviction and Lower Resist break immunes with a caveat; if the amount being subtracted isn't enough to put the monster lower than 95%, the Conviction/LR doesn't break the immunity. My Avenger's level 27 conviction doesn't break the cold immunity for lots of things, the one that sticks out in my mind are the mages in the Chaos Sanctuary. A real pain, when they IM me, and my Cold Sorceress friend can't do a thing to help.

As for Lower Resist, the same applies, except it breaks less immunities since it subracts less from the monster's resistance. Stack Lower Resist and Conviction together, though...