Since Endarire hasn't really voiced anything and we're following this line pretty well I guess we're pretty much spot on.
Playing into the Constantine theme, ie a guy that was going to hell seeks to "win" his way into heaven by killing evil eventually does via self sacrifice only to be resurrected by evil in hopes that he'll screw up again, using the mechanical rules of acquiring an Alignment subtype to maintain qualifications but also paying attention to Exalted requirements. You could go two ways, evil gone good or good pretending to be evil.
For example if Alignment change is ok you could do something like
Ranger 1 (fe:arcanists) / Warblade 1 (blood to water stance) / X Y / @7 Disciple of Dispater 4 (iron power) / X Y / @16 Harper Paragon (fe:evil) 2 / X Y
Feats: Favored Critical(arcanist)6th/9th, Sacred Vow12th, Vow of Obedience15th, Favored Critical(evil)18th
Where levels 11 to 12 is your transitional area and sacrificing all but your combat style. It's very much evil trying to save it's self that eventually does concept.
Or a build like this one, which gets out of an Alignment change and will probably see more forum reposts because of it.
Ranger 1 (fe:arcanists) / Warblade 1 (blood to water stance) / X Y / @6Harper Paragon (fe:evil) 2 / X Y / @11+ Disciple of Dispater 4 (iron power) / X Y
Feats: Sacred Vow1st, Vow of Obedience3rd Favored Critical(arcanist)6th/9th, Favored Critical(evil)6th/9th.
Where you slip into the church's special forces, pick up your secret identity tag and convince your target group you're a homie.
You should have room to figure out if you want Arcane Dualist or even Dervish.