I have a few questions conerning mana barrier, any help would be appreciated:
1. Can you cast a mana barrier throught peoples and object, don't see anything in the rule preventing it, except maybe if they are dual nature or in the astral, as from what I understand, the barrier would then be solid to these people/spirit?
This new edition doesn't give very much word count at all describing how the in-game metaphysics work. For example, in some prior editions it was possible for an astral form to pass through another, and in others it wasn't. For example, simply draping a wall with living ivy is not a barrier to astral projection, or it is, depending on which edition you're playing!
Until such time that your question is officially answered via a Rulebook FAQ, or the magic expansion sourcebook, my personal opinion is you should assume the more conservative/restrictive option. I would say that no, you cannot make a mana barrier spring into being right through someone's aura. Until such time there's something saying that yes, you can.
2. Would casting a mana barrier throught a spellcaster that is sustaining a spell cause him to potentially loose it (magic*s vs barrier rating *2)? Likewise, if I cast the barrier in an ongoing spell (illusion, animate X, other barrier, etc), would that cause the same Magic Rating*2 vs Barrier rating*2 test also?
See my above answer. However, if you cast it right in front of a moving spellcaster, in such a way that he's guaranteed to collide with it, we basically have the same situation with only a pedantic difference, yes?
In such a case, we have guidance on how to handle this on page 162:
An item normally blocked by a mana barrier
might run into one by being in an elevator, van,
or something else that is unknowingly crossing a
barrier. In these cases, roll an Opposed test; living
beings roll Magic + Charisma, foci roll Force
x 2, preparations roll Potency x 2, barriers roll
Structure rating x 2, spells roll caster’s Magic x 2.
Whatever side loses is disrupted--spells dissipate,
foci deactivate, spirits return to their home metaplane,
and living beings are knocked unconscious
with a full Stun Condition Monitor. In cases of a
tie, everything disrupts.
I'm looking for ways to dispell magic more effectively than the very disappointing Despelling Skill. Anything with a 6+ drain becomes extremely difficult to dispel, which incidentally, barrier are part of.
I'll be honest... this line made me question whether you're even asking about Sixth World Edition. Dispelling works SO MUCH BETTER than in Fifth Edition... but if you didn't play it that perspective doesn't help you much does it?
Note that Dispelling isn't an all-or-nothing attempt. Per page 143, "Net hits on this test cancel net hits on the spell on a one-to-one basis; when net hits reach zero, the spell is completely dispelled." If the spell you want to dispell was originally cast with 4 net hits, you can get 2 net hits on the 1st dispelling test, then you only need 2 more on the next dispelling test to finish it off.
Now, yes, some spells have significant drain values and when you double that value, you might not be able to reliably score ANY net hits. I believe that's your main point? To that, I say, without snark, "Get a bigger dice pool yourself, then." A mana barrier with 6 drain value is rolling 12 dice against you. You absolutely "should" be rolling at least 12 dice in anything you plan on being "good" at. Absolutely consider getting a Dispelling specialization for your Sorcery skill if you plan on making that a big part of your character. Ditto for buying and binding a Counterspelling (or even a Power!) Focus.
Ok, so what if you simply don't have 12 dice? Consider using Teamwork to increase your dice pool. And edge expenditures to minimize the disparity between dice pools. A 6DV mana barrier is going to roll 12 dice. Odds are, that's going to be about 4 hits. Ok, so spend 4 Edge to make the mana barrier reroll those 4 hits, which probably ends up being 1-2 hits after it's said and done.
