Seemingly non-interrogative use of sentence-ending か I keep on coming across the particle at the end of sentences without it having a clear or necessary interrogative nuance. An example. The 1st Angel in Neon Genesis Evangelion is regenerating itself after the first raid: . Why would they introduce an interrogative nuance into what was already a predicted outcome? I get the impression that Japanese speech encourages the use of without any specific interrogative or grammatical purpose other than providing a strong phonetic closure to a sentence? Can anyone confirm or dispel this impression?

This function of this is not purely phonetic, but rather serves to make the sentence less of a outward statement and more of a self-directed or self-reflecting one.

It makes the information value of sentence primarily be “I had considered ~ previously but wasn’t sure, but in the end it indeed it is , huh...”

It’s often is accompanied by (or playing a similar role in this sentence). Even when such an adverb isn’t present, you can imagine it being there. E.g. {HHL} can basically be expanded to .