Old Man and Mr. Yan mentioned the Python Demon, which is actually akin to the snake spirits of the Lin family from the Eastern Land's beastkin.
It's just that they are a bit lower in rank than dragons, and this isn't Durin spouting nonsense; this hierarchy was established during the creation of these beings, particularly for the Candle Dragon, whose suppression of the Python Demon is nearly all-encompassing.
Yet, the Python Demons don't particularly care about their relationship with the Candle Dragons—many Python Demon clans even cling to the Candle Dragon.
After all, if you can't defeat them, it might as well be worth joining them.
And these creatures were quite happy to serve Durin, even though they were quickly transferred to Pool's command considering Pool is Durin's elder brother and also in charge of managing Durin's territory, the Python Demons were still more than happy to stay.