Due to recent misconceptions, I've decided to make an informative post on the god Ullr. Well, on what we think we know of the god Ullr. I word it like that because not much is known of Ullr, he is mentioned in the Lore scarcely, and most of the time he is being referenced to indirectly. What we know of him is merely speculation, so if you have heard anything other than what I write here please share or correct.
Scholars have studied many ancient texts, and yet very little is known of Ullr. In fact, it is even unclear as to what his role in the Norse Pantheon is. To some he is known as the god of the hunt, as well as the god of winter, however there is little to no evidence in any form of Northern Lore that can support this. The idea of this most likely came from non-literary depictions of him, stone paintings and carvings with his name bearing an image of a man wielding a bow and wearing what appeared to be ice skates. However, much like the god Tyr, there are references to him in literature and stoneworks long before the first image of Odin was seen. This lead to a theory that Ullr at one point had an extremely significant role to the ancient Northern cultures, but that role has been lost throughout history. According to what we have, Ullr is the son of the goddess Sif, and stepson to the god Thor. Some kennings claim he was a skilled archer, as well as ice skater, being very handsome, warlike, and a skilled fighter; even to this day it is not uncommon for one to call upon the help of Ullr during a duel. A common phrase referencing to Ullr is "Ullr's Ship", a kenning usually meaning a shield. Some believe that this is because he once sailed across the ocean on a shield; but this tale was lost. Some believe he was a member of the Vanir, seeing as though many of the Vanir have a connection with the oceans and seas. In my own personal opinion, I believe this could be very true, as many depictions show him as more a gentle soul than the Aesir. His home is known as Ydalir, or "Yew Dale", which makes sense because many high quality bows during that time were made from yew wood.
In one of the tales of Odin, the Allfather is stuck between two flames, and promises the ''Blessing of Ullr and all the gods''; in the Atlakvida the most serious of oaths is sworn on the ring of Ullr; his name was typically found with the word "hof" meaning "temple" which suggests there was organized and frequent worship of this deity; it is even speculated that he temporarily took rule of Asgard in Odin's absence, but that is highly doubtful.
Ullr, whether he be the God of Winter, or the Hunt, or both, or neither will always be the God shrouded in mystery, and of Forgotten Purpose. There is enough evidence supporting that he was a very important figure, however no one will know why, not until we find that one last piece of ancient text revealing to us our lost god.