Do you speak Russian? Do you see what it says in the last sentence? But regardless, thank you very much for this post, as it actually confirms that gal means black. Which was the important thing.

So ugalj means u + galj = into + black, sooth, charcoal…

You see what annoys me about you is that you know all these references but you are unable to connect them. Or maybe you are afraid to do so even when official etymology has no explanation.

We could cooperate, but instead you decided to fight.