Dead Zone

==== Dead Zone ====
Ninjutsu (Wind);
Level: 	B
Hand Seals: 	None
Casting Time:	1 Standard Action
Range: 	60ft.
Area: 	Dome
Duration: 	1 round/CL
Saving Throw:	None
Chakra oozes outwards, filling a 60ft wide radius. Within this radius the invisible chakra is molded into wind, more specifically pure oxygen. Any and all creatures within this zone that require a normal balance of oxygen and other atmospheric gases to breathe will suffocate to death.
Round 1: During the first round, those within the field start to find breathing difficult. Their breaths subtly become deeper in an attempt to draw in more air. After remaining in the field for one round the DC for your jutsu decreases by 20, as well as your BaB on all weapons and unarmed strikes. Those within this field for one round are also inflicted with ability damage to their Con equal to CL/5. There is a 25% chance of creature's in the field falling unconcoius.
Round 2: Subtly gasps for air become extremely noticeable at this point, as those within the field begin to suffocate. On the second round you remain within the field, your DC for jutsu decreases by 20 again, as well as your BaB for all weapons and unarmed strikes. Any dodge bonus to AC you possess is ignored and you suffer another CL/5 points of Con damage. There is now a 50% chance of falling unconcious.
Round 3: Upon reaching three rounds within the field, you become unable to do anything except gasp for breath. Collapsing to the floor, your vision fades away and you die.
Any creature that exits the field before the third round, loses all penalties, though any damage sustained remains.