[Grammar] Dare as a modal verb in the past

[5jj]

I've got an impression that you're discussing two different verbs - dare as a modal verb, and dare as a transitive verb.

The whole thing is unclear. We sometimes see DARE with the auxiliary DO, or in a regular past tense form dared (so, not a modal then), but without to following.

As to the discussion of will+DARE, I think the question was not so much as whether DARE is a modal in such constructions (clearly, it can't be), but how natural it sounds.