WM would alter the area to create a strong magnetic field in the room. It would lower the evasion of everyone in the room based on how much metal armor they are wearing. Secondary effect with weapons. Thinking either lowers effectiveness with metal weapons, or spell would pulse every so often and have a chance to pull metal weapons from hand with RT to try and pick it back up.

Abison/Rystien

The effect is only good for the first shot with Ballista, (tho the caster can rub the ballista to stop the effect) will attempt to yank all in the room to the ground, depending on how much metal-armor they are wearing. Dont' know if it attempts to yank weapons out of hands, or if it hinders any type of attack. Consecutive reloads aren't as powerful of shots, nor do they have the magnetic effect.