Balyne le Saveage’s character can be gleaned from the following passage:
Than hit befalle so that tyme there was a poore knyght with kynge Arthure that had bene presonere with hym half a yere for sleyng of a knyght which was cosyne unto kynge Arthure. And the name of thys knyght was called Balyne, and by good meanys of the barownes he was delyverde oute of preson, for he was a good man named of his body. (Malory, Works, 1971 collection ed. by Vinaver, p. 39)
The two main points that emerge are 1) that Balin often kills when he shouldn’t and 2) that Balin is self-righteous (because “a good man named of his body” may mean “a man who esteemed himself good”). The latter defect may account for the former, but in any case the combination of the two defects isn’t promising.
Balin’s self-righteousness becomes evident a few lines later, when he draws the sword from the damsel’s scabbard (which no others had been able to do) and is overly glad to believe her claim (suspected by Merlin to be counterfeit) that only good knights could so obtain the weapon. He refuses her request that he return it to her and gazes upon the false proof of his goodness with immoderate pleasure.
Balin’s tendency to kill too much – to kill at least one person too many – is evident throughout the rest of the story. First, he kills the Lady of the Lake, whom be holds responsible for the death of his mother (his righteous excuse). Then, he slays Sir Launceor, who indeed had it coming, but wrongfully watches when Launceor’s paramour kills herself out of grief. Later, he shows Sir Garnyssh the infidelity of his paramour, causing Garnyssh, likewise, to kill himself. These latter two deaths, among many that occur wherever Balin goes, are deaths of love, which, if God is love, can perhaps be described as sacrilegious. Of course, the ultimate unfortunate blow is the Dolorous Stroke, a stab at good King Pellam collateral to the justifiable killing of the evil knight Garlon, which results in the blighting of three kingdoms.
I hypothesize that Balin’s “two swords” are not swords at all but the representation of his penchant for excess, especially excessive self-regard. One sword should be enough for any knight. Readers of the story may try to count the swords Balin carries at any given time, and unless there is an unnamed sword or swords in his valise, it never amounts to two. The meaning of the story might be that all faith in oneself is misplaced (for it belongs with You Know Whom) and can do tremendous damage in proportion to its strength – or in proportion to the strength of its possessor.