Torm

What we know

Champion god of paladins; protects those weaker than them (Session 2 @ 02:34:27)
Sildir heard divine voice during long rest at watchtower; spoke oath words and received Torm's emblem burning onto armor (Session 2 @ 02:33:09)
Sildir chose Torm over a second, darker voice offering vengeance champion path (Session 2 @ 02:33:09)
Same second voice counseled Sildir with Torm before Eliza's execution (Session 6 @ 02:44:58)
Session 19: voice revisited Sildir in dream offering battle strength amid Strahd imagery—party identifies this as the second voice, not Strahd (Session 19 @ 14:37)
Irredel stated Torm views Tyr, her god, as a father (Session 2 @ 02:48:25)
Sildir swore Oath of Vengeance to Torm at level 3 (Session 2 @ 02:39:05)

Vision to Sildir during long rest after escaping Durst Manor (Session 2 @ 02:33:09).

Blinding light from Sildir's armor illuminated watchtower when oath accepted (Session 2 @ 02:36:11)

Unconfirmed: identity of second divine voice that offered vengeance (Session 2 @ 02:33:09)