The Dauntless Defender

A dauntless defender's place is on the front line, preventing attacks from reaching his allies and shrugging off blows that would crush other men. Most of the dauntless defender's iconic class features are designed to function while he is wielding a tower shield with both hands. It is an unorthodox strategy that can only be fully utilized by one who has committed to the idea that keeping your allies safe and unharmed is more important than inflicting harm upon your foes.

Adjustments

A dauntless defender uses a d12 (instead of a d10) as his HD.
A dauntless defender's base attack bonus scales from +1 at 1st level to +25 at 20th level (instead of scaling from +1 at 1st level to +20 at 20th level).
A dauntless defender is not proficient with any weapons.

Tower Shield Training (Ex)

Starting at 1st level, while a dauntless defender is wielding a tower shield with both hands:

The maximum dexterity bonus of his tower shield is increased from 2 to 4.
The armor check penalty of his tower shield is reduced from 10 to 2.
The spell failure chance of his tower shield is increased from 50% to 100%.
The spell failure chance of his tower shield applies to all types of spellcasting (rather than only arcane spellcasting).

This ability replaces Armor Training and Weapon Training

Tower Shield Bash & Tower Shield Deployment

At 1st level, a dauntless defender gains the Tower Shield Bash and Tower Shield Deployment abilities.

Tower Shield Bash (Ex)
While a dauntless defender is wielding a tower shield with both hands, he can use it in order to perform a tower shield bash.

Tower Shield Deployment (Ex)
Whenever a dauntless defender positions his tower shield in order to obtain total cover (as explained in the tower shield's description), the total cover that he obtains is applied not only against targeted attacks, but also against targeted effects (such as targeted spells, targeted spell like abilities, etc.).

These abilities replaces Bravery

Brothers in Arms (Su)

Starting at 1st level, a dauntless defender gains the ability to designate an ally as his partner by rigorously training with them for 10 (uninterrupted) minutes. Once a dauntless defender has designated an ally as his partner, the two of them remain linked by the effect of this ability for 24 hours, unless the dauntless defender designates a new partner, in which case their link breaks prematurely. A dauntless defender always knows how much distance there is between his partner's location and his own location (as well as the direction in which his partner is located relative to him) while both he and his partner are on the same plane of existence. While a dauntless defender is wielding a tower shield with both hands, both he and his partner are subject to the effects of one of the following abilities (chosen by the dauntless defender upon designating that ally as his partner).
At 3rd level, a dauntless defender becomes able to choose two of the following abilities (instead of one) when designating an ally as his partner.
At 7th level, a dauntless defender becomes able to choose three of the following abilities (instead of one) when designating an ally as his partner.

This ability replaces Armor Mastery and Weapon Mastery

Modified Bonus Feats (Ex)

At 2nd, 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, and 20th level, a dauntless defender learns two additional feats, independent of those gained from normal advancement. These feats must be chosen from the following list: Adept Reactions, Alertness, Ambush Awareness, Antagonize, Anticipate Dodge, Armor Adept, Back to Back, Blundering Defense [1], Bodyguard, Broken Wing Gambit, But a Scratch, Cautious Fighter [1], Center of Attention, Combat Patrol [2], Combat Reflexes, Concussive Blow, Coordinated Defense, Coordinated Distraction, Coordinated Maneuvers, Counter Reflexes, Deceitful, Defended Movement, Defensive Expertise, Derisive Rebuke, Diehard, Dire Defense, Dire Offense, Dire Preservation, Dire Reduction, Dire Resistance, Dire Upgrade, Disruptive, Dodge, Efficient Evacuation, Endurance, Feint Defender, Fleet [3], Following Step, Gang Up, Got Your Back, Great Fortitude, Greater Ray Shield, Greater Shield Focus, Greater Shield Specialization, Grudge Fighter [4], Guarded Mobility, Harrying Partners, Heroic Defiance, Heroic Recovery, Improved Aid, Improved Combat Reflexes, Improved Initiative, Improved Shield Bash [5], In Harm's Way, Iron Will, Leg Breaker, Lightning Reflexes, Lookout, Loyal to the Death [6], Missile Shield, Mobility, Outflank, Paired Opportunists, Persuasive, Ray Shield, Reverse Feint [4], Self Sufficient, Shake It Off, Shatterspell [7], Shield Block, Shield Focus, Shield Fortification, Shield Specialization, Shield Wall, Shrewd Tactician, Spellbreaker, Stand Still, Step Up, Step Up and Strike, Stumbling Bash, Support Patrol, Team Up, Toppling Bash, Toughness, Unencumbered, Vanguard Aegis, Vanguard Bulwark, Vanguard Deflection, Vanguard Interception, Versatile Aid, Wounded Paw Gambit, Zealous Aid.

This ability modifies Bonus Feats

Modifications:
[1] You can ignore the "halfling" prerequisite for this feat.
[2] This feat gains an additional effect: "While you have a combat patrol active, your opponents treat your threatened area as difficult terrain."
[3] The bonus that you gain from the effect of this feat is increased from 5 ft. to 10 ft.
[4] You can ignore the "orc" prerequisite for this feat.
[5] This feat gains an additional effect: "The amount of damage that is dealt by your tower shield bash is increased from 1d10 to 2d10."
[6] You can ignore the "human" prerequisite for this feat.
[7] You can ignore the "dwarf" prerequisite for this feat.