Say, around what level do Legendary Dragons appear? Been dealing with Ancients so far so I guess soon? I'm wondering since I have no idea what to expect with them. Some dual power attacks let me kill within 5 to 7 hits, and any change on their appearance? (I've never once fought one and I'm kind of scared to tbh XD)
Legendary Dragons can appear from level 75 onwards. My first one was a frost dragon and I came upon it attacking Halted Stream Camp. It wasn't interested in me or my follower and horse at all until it had finished off the bandits. By that time it's health level was at a manageable level and it didn't seem as tough killing it.
As for appearance this is from the wiki: Unlike other breeds of dragon, legendary dragons have distinctive thick, curved horns. They have a black and purple scale color. They are also unique in having what appears to be compound eyes, formed of multiple "eyes" in a single socket.
I actually find Revered Dragons to be much tougher. Once you hit the level to have them appear, they are fricken everywhere. Even landing in the Blue Palace courtyard!