Does anyone have any specific canon references to back up this reference from the Helm wiki?:
The only god who could be considered a full ally of the Watcher is Torm, the god of paladins. Strongly-held ideological differences have caused a great rivalry verging on hatred between the clergy of the two gods, but the deities themselves remain close.
Particularly, what are these "strongly-held ideological differences" that would pull apart the two churches?
Anything written that can related to the Silver Marches in particular?
The death and destruction that result from the avatar crisis earned the vigilant one and his followers a great deal of enmity, from members of other faiths, particularly those of Mystra, Bane and Torm. In the South, Helm's role during teh time of troubles was not viewed as unfavorably as it was in the North,...
Of the good aligned deities only Torm truly understands Helm's unbending commitment to his charge. Relations between the Loyal Fury and the Vigilant One are strong, enough that the two churches have grudgingly begun to heal the rift between them, at the command of their respective deities.
Current PC: Gareth Darkriver, errant knight of Kelemvor
Se'rie Arnimane: Time is of the essence!
Nawiel Di'malie: Shush! we're celebrating!
The summary version would be, during the Time of Troubles, when Ao cast all the gods out of the heavens, he retained Helm with full powers as the guardian of the celestial stairs that would have allowed the gods to return to the heavens. Torm and Mystra were among the demoted dieties that actively sought to counter the plans of the Three who stole the tablets of fate (Bane, Bhaal, and Myrkul), causing the godswar in the first place. When the identities of the three gods responsible were learned, Mystra tried to return to the heavens to present this to Ao, and was slain by Helm, performing his duty of guardianship explicitly, as he had been commanded not to allow any of the dieties to return unless they bore the tablets of fate.
Torm, on the other hand, later died while destroying the avatar of Bane in a pitched battle over the city of Tantras.
I would assume that the philosophical tensions between the clergy run as follows: Tormites might consider diligence without consideration of morality or honor abhorant, while Helmites might equally feel that obedient vigililance is weakened by irrelevant personal concerns. It's basically a LG vs LN argument, writ large by deicide. Torm was out in the trenches dying for the just cause, while helm was standing on the sidelines, retaining all his powers, and killing the "good guys" who tried to get past him.
When I was playing a Mystran cleric, I tried to convey a certain discomfort and distrust of Helmites along the same lines.
On a more mundane level, the involvement of the church of Helm in Maztican atrocities hasn't exactly endeared them with anyone of Good alignment either.