Noah mosaic (source: wikipedia)

What is the literature genre of "saga"? Karl Barth identifies the Creation accounts as an examples of the saga genre. Saga is not limited to the Proto-History of Genesis; it is utilized throughout the scriptures. See, for an example, Karl Barth's use of saga in his exposition of the Twelve Spies in the Land of Canaan (Num 13-14).

In the Church Dogmatics III/1, Karl Barth provides the following definition of saga:

Karl Barth's definition of 'saga':

"I am using saga in the sense of an intuitive and poetic picture of a pre-historical reality of history which is enacted once and for all within the confines of time and space. Legend and anecdote are to be regarded as a degenerate form of saga: legend as the depiction in saga form of a concrete individual personality; and anecdote as the sudden illumination in saga form either of a personality of this kind or of a concretely historical situation. If the concept of myth proves inadequate—as is still to be shown—it is obvious that the only concept to describe the biblical history of creation is that of saga."

Barth, Karl. "Church Dogmatics Study Edition 21" Ed. T. F. Torrance and G.W. Bromiley. III.1 The Doctrine of Creation. Trans. G. W. Bromiley. London: T & T Clark, 2010. 81. Print.

Barth's preface to his definition of 'saga' includes a helpful apology for the genre of saga against those who believe all forms of purely non-historical narratives are inferior and unacceptable for Scripture to utilize.

We must dismiss and resist to the very last any idea of the inferiority or untrustworthiness or even worthlessness of a "non-historical" depiction and narration of history. This is in face only a ridiculous and middle-class habit of the modern Western mind which is supremely phantasmic in its chronic lack of imaginative phantasy, and hopes to rid itself of its complexes through suppression. This habit has really no claim to the dignity and validity which it pretends. It acts as if only "historical" history were genuine history, and "non-historical" false. The obvious result is to banish from the portrayal and understanding of history all immediacy of history to God on the pretext of its non-historicity, dissolving it into a bare idea! When this is done, the horizon of history necessarily becomes what it is desired to be—a highly unreal history, a more or less explicit myth, in the poor light of which the historical, what is supposed to be the only genuine history, can only seem to be an ocean of tedious inconsequence and therefore demonic chaos. We must not on any account take this course. In no way is it necessary or obligatory to maintain this rigid attitude to the "non-historical" reality, conception and description of history. On the contrary, it is necessary and obligatory to realize the face and manner that in genuine history the "historical" and "non-historical" accompany each other and belong together.

In addition to the "historical" there has always been a legitimate "non-historical" and pre-historical view of history, and its "non-historical" and pre-historical depiction in the form of saga.

As far as I can see and understand (cf. the competent articles in RGG by H. Gunkel, W. Baumgartner, O. Ruhle, P. Tillich and R. Bultmann), modern ethnology and religious science cannot give us any illuminating and acknowledged clarification, distinction and co-ordination of the terms myth, saga, fable, legend and anecdote, let alone any useful definition of their relationship to history and historical scholarship. The non-specialist must try to find his own bearings in this sphere.

Ibid.

Barth's postscript to his definition of 'saga' contains an equally helpful explanation that saga is embedded in the Biblical witness, such that it is not possible to say whether any text of Scripture is purely saga or void of saga in the Scriptures.

That it does actually contain a good deal of saga (and even legend and anecdote) is due to the nature and theme of the biblical witness. It also contains "history," but usually with a more or less strong wrapping of saga. This is inevitable where the immediacy of history to God is prominent, as in the histories which the Bible relates. On the other hand, it also contains a good deal of saga with historical wrappings, and this again is not surprising when by far the greater part of the events related by it takes place in the sphere where "history" and "historical accounts" are at least possible in principle. To put it cautiously, it contains little pure "history" and little pure saga, and little of both that can be unequivocally recognized as the one or the other. The two elements are usually mixed. In the Bible we usually have to reckon with both history and saga.

It is to be noted at this point that the idea that the Bible declares the Word of God only when it speaks historically is one which must be abandoned, especially in the Christian Church.

Ibid.

The prefix, definition and postfix form a direct quotation from Karl Barth's Church Dogmatics III/1. Most of the definitions of saga quote from abridged versions of these quotes.