Do you cut your range in half throwing a grenade when Mags has Magnetic Shield?

And another debate, is it the character or the grenade making the attack? So do you get hindering bonuses on defense against grenades?

It helps to quote the relevant things when asking a question:

Magneto's Magnetic Shield halves the character's range value. But throwing a grenade has a set range value, which is not determined by the character's own range value - but has a range value all of it's own. Since Magneto's shield halve's character's range values... the grenades would not be affected.



And actually, to further reinforce.... The Mauler figure from the Gears of War set for example has a 0 range, but still has the ability to Throw a Grenade.

It's the character, using the throw a grenade ability. The reason you get the hindering terrain bonus against grenades (I think) is because the Throwing A Grenade text states that you're making a ranged attack.

From what I can tell, the hindering bonus doesn't apply to grenades, since when you throw a grenade the line of fire is drawn to a target square, not a character.

You would be correct. That is why I put "I think". I wasn't quite sure on that one.

To further reinforce this, reference TK from the player's guide...

Since you are drawing line of fire from a character to the square, and not from character to character (furthermore, characters are ignored for line of sight, per the wording of the Throw a Grenade text), as such the hindering terrain bonus would not apply.

Good catch.

what about Energy Shield/Deflection when it's come to grenades being throw at an squre. like will they be able to get the +2 to thiers defense?

Energy Shield/Deflection: Modify this character's defense value by +2 against ranged combat attacks.

Give the character a power action, decrease the number of grenades in your grenade pool by 1 (if greater then 0), and choose a type of grenade listed on this card. Choose a target square within 5 squares and line of fire (ignoring characters for line of fire purposes). Make a ranged combat attack targeting all characters occupying or adjacent to the target square. Deal damage to each character hit based only on the type of grenade chosen.

Sure looks like it works against grenades to me.

That was my thoughts

Applies when Throw a Grenade is used:

Energy Shield/Deflection
Shape Change
Super Senses
Damage reduction powers (when the grenade damage isn't penetrating)
Crit hits/misses (as long as the grenade's base damage isn't 'no damage')
Any power that triggers when a character is the target of a ranged combat attack

Doesn't apply when Throw a Grenade is used:

Stealth
Hindering