Also I warmly recommend instead spiked chain you would go to use mighty bladed whip. As whip is still exotic weapon to you even as figther and blackguard and paladin of tyranny (I assume you took weapon focus:whip to qualify for pious templar).
Also I assume reason for paladin of tyranny (btw, Lolth uses paladin of slaugther than tyranny) and blackguard levels is intended to double stack the charisma bonus to saves with divine grace and dark blessing features? Sorry, I house rule that they do not stack; it's one or the other
So if rebuild your levels and feats;
Figther 2/Paladin of Slaugther 4*/Pious Templar 6.
*=Use divine warrior variant from Complete Champion. Meaning no spellcasting from paladin but bonus feat instead.
(1): Exotic Weapon proficiency (Whip)
(fig1): Weapon Focus (whip)
(fig2): Combat Expertise
(3): True Believer
(PaloSla4): Divine Might (by sacrifcing one rebuke undead per day you add charisma bonus to melee damage rolls for 1 round as a free action)
(6): Improved Trip
(Pious Templar 3): Weapon Specialization (Whip)
(9): Extra Smites (+2 extra Pious Templar smites)
(Pious Templar 4): Power Attack
(12): Mighty Smites [tactical] or Cleave
I removed flaws as if you can make decent build without them then your better off already
Note; You should use bladed mighty whip. Mighty whip allows use strenght mod with whip attacks and bladed whip does lethal damage even armored foes. Also with 6 Pious Templar levels you get third level blackguard spells already (which is damn good) and also DR 1/- along with nice smite attacks. Also Mighty Smites tactical feat from Complete Champion allows maximisize smite attacks to do some nice tricks with your smite attacks.