Werebear!Halsin
I've seen some references to werebear!Halsin and it's got me thinking about how that would work in the context of the game canon, and the thing is... it really does. So here are some of the points that I've considered about it and how I think it most likely to work. As usual, I'll be working to align with current 5e lore unless stated otherwise, but drawing from 3.5e in some areas to add depth, because let's be real, that's what it's for.
Baseline Info
Werebears are the most controlled - and Good-aligned - of the Forgotten Realms lycanthropes. It is extremely uncommon for them to attack indiscriminately or act with evil intent.
Werebears tend toward the solitary and typically avoid areas of heavy civilization, preferring the wilds. They will choose a large swathe of territory that falls under their protection, and treat guarding it from evil- and ill-intentioned interlopers as their primary responsibility.
It is quite common for them to become rangers, given their attunement to nature and their solitary habits.
They can be either born naturally from one or both parents being werebears, or the curse can be passed on via bite.
Werebears are extremely discriminating and careful about who they entrust their power and/or curse (depending on who you ask) to. They will choose someone that they know to share the same values, and will stay with them and train them as they acclimate to their new existence.
As It Relates to Halsin
He talks about having grown up spending a great deal of time in the forests of his home, playing with Thaniel, who no one else had heard of. This tells us that Halsin had, even as a child, an uncommonly strong connection to the natural world and its magics.
It is extremely possible that the forests of his home were also within the territory of a local werebear, and this devotion of Halsin's to nature would have been exactly in line with their own creed, making him of great interest to them as a potential apprentice.
Halsin also shares that there came a point when he realized that he could not merely be a companion to Thaniel/nature, he also had to be his/its protector. This makes sense as a point where he would feel prepared to take on the additional power and responsibility both that lycanthropy would bring.
This makes a lot of sense for his character as an adult as well: the way he has strong emotions but a great deal of practice controlling them, the way he prefers to be measured in his responses and judgements as much as possible, his care for his community, etc. I also think it even makes sense that it would not be something he would tell to a player character - he just wouldn't even see a need to. From his response if you share your opinion of his choice of successor, it is clear that he is not overly concerned with outside approval, which speaks to the way he is very settled in himself and feels no need to proactively defend anything about his being. Additionally, especially with his level of control, it simply would be none of the business of general acquaintances.














