It seems a lot more likely that the Nightsong tries to heal you with magic from Shar and it doesn't work than the tadpole literally being more powerful than Shar.
"That thing in your head must be incredibly powerful to resist a godess" t. Nightsong (Source)
Could just be talking as if her powers = Shar's powers like some clerics/priests tend to do. Gods aren't supposed to interfere directly with the mortal world.
I listened to Mizora's line (Wyll's patron). She mention
that Spike is asking about a weapon that was on the Nautiloid.
There is something weird about that. Everyone know there was a weapon on the ship. Nobody seems to know what it is or who as it.
And the game use the term for two different things in-game: - the mysterious artifacts - Shadowheart (someone told her she was a "beautiful weapon" in her mind while in the ship).
