Sphere-specific drawbacks must be chosen when a practitioner first gains the associated sphere, and grant the practitioner an extra combat talent in the prerequisite sphere. Drawbacks may be removed in place of gaining a new talent through your class progression or by taking the Extra Combat Talent feat.
Wiki Note: If a Base Sphere grants an additional talent (such as via a package selection or drawback) the additional talents do not count as talents spent for abilities that count the number of talents spent in a sphere. (This most often applies to gaining skill points or improving unarmed damage.)
Utility Starts
The [utility start] tag is described in Spheres of Guile. It is only possible to take advantage of a combat sphere as a [utility] talent if your game includes a way to gain combat talents restricted to those with the [utility] tag, such as using one of the variants in Chapter 1.
Piecemeal Utility Starts: If you have a progression or optional replacement that grants a [utility] combat talent or a [utility] magic talent, you can use it to gain a base sphere if you apply a drawback or combination of drawbacks that removes all of that base sphere’s benefits other than skill ranks and [utility] talents (and actions necessary to use such talents).
Aggressive Defense
You do not increase your shield bonus to AC when using active defense. You gain Punch Block with this drawback, and must apply its effects whenever you use active defense.
Incompatible: Hostile Shield, Mobile Bulwark, Passive Blocker.
Hostile Shield
You do not gain the active defense ability and cannot select (deflect) talents or other talents that rely on active defense. You gain Bashing Shield with this drawback.
Incompatible: Passive Blocker.
Mobile Bulwark
You do not gain the active defense ability and cannot select (deflect) talents or other talents that rely on active defense. You gain Flexible Cover with this drawback.
Incompatible: Hostile Shield, Passive Blocker.
Passive Blocker
You do not gain the active defense ability and cannot take (deflect) talents or other talents that require the use of active defense. You gain Deflecting Shield with this drawback.