
If Beren kills the Dwarves and the Lord of Nogrod, that act becomes justifiable, and perhaps even the right thing to do, simply due to the fact that one of the two true heroes of the First Age is doing it. Like I said above, Beren and Lúthien are good people who do good things, and those things are good because of who’s doing them. However, being bondmates is more than just a weapon or a means of being stronger in battle- it's an intimate and close relationship, and bondmates genuinely care about each other, not just about how they can use each other to make themselves stronger. And then the someone would take out a piece of their Grace and give it to the first angel, and they'd be "bondmates." Doing so is advantageous to angels because the psychic connections that all angels have with each other are stronger with their bondmate, and being in the presence of their bondmate makes their Graces stronger (which is why Balthazar's death made an explosion of Grace bigger than any other angel death in the show- because he was killed by Cas, his bondmate, which released a large amount of energy that Cas then absorbed to use in the fight against Raphael ��😭). I think an angel would essentially take out a piece of their Grace and give it to someone they care about, then that someone would take the Grace and sort of "sew" it into the fabric of their own Grace.

There's also the idea of angels having "bondmates," which I suppose would be a bit like how shadowhunters become parabati.
