Since the Devoted Defender isn't core, I'll post it here.
Devoted Defender
HD d12
Requirements:
BAB +5
Weapon Focus (any), Alertness
Search 4, Spot 4, Sense Motive 4
Skills: Climb, Innuendo, Jump, LIsten, Profession, Sense Motive, Search, Spot
2+ Int Modifier
BAB: +1 per level
Saves: Good Reflex and Fortitude, Poor Will
Features:
AC Bonus: The Devoted Defender gains a dodge bonus to his AC. This is equal to his class level divided by 2 (min 1).
Harms Way: At 1st level, the DD can switch places with a charge under attack if within 5 feet, before the attack is made. You are attacked instead of the charge.
Defensive Strike: At 2nd level, the DD can make an AoO against any opponent who attacks his charge in melee. He gains a +1 bonus to this attack for every 2 levels after 2nd.
Deflect Attack: At 3rd level, the DD can attempt to parry a melee attack against his charge, if he is within 5 feet and holding a melee weapon or shield. Once per round when his charge would normally be hit by an attack, the DD can make an opposed attack roll. If successful, the attack is deflected. the DD gains a competence bonus to this attack roll for every 2 levels after 3rd.
Finally, for a feat I may to use, Shield Expert: Prereq BAB +3, Shield Prof.
When making an off-hand attack with your shield, you retain the Shield's AC bonus for that round.
Is my character concept acceptable?
