Edit: In light of the info added to the Q, there may be hope for the group yet. Other answers cover that angle enough so I won't edit the answer below.
I don't think this is the answer you want to hear, but in my opinion there is no way to fix this.
Those darts are such a bad, horrifying idea, that it shows the DM is simply out of their league trying to be a DM. And that sword is frankly no better. If DM allows this, they are probably doing it intentionally to troll and bully you together with Hannah, maybe to see how far you can be dragged along. Alternatively they are simply clueless, and from your description I would estimate clueless beyond fixing by discussion. They may become a good DM with more experience, but it won't happen fast.
I would just simply leave, and not play with this DM again.
I have been in a bit of similar situation. Very remotely similar, this DM of mine was actually mostly very good, there just were some similar issues which still soured the experience for me. It was quite hard for me to leave (it basically took TPK and end of the campaign, very convenient moment to drop out). But in afterthought, leaving was excellent decision. I am now in a few groups which are more to my liking, and I think the group I left is also better off with one less frustrated player.
So leaving can be hard. I would bluntly state that "Hey guys, I find the sword and the darts of Hannah not fun, and don't want to play that kind of a game any more. What shall we do, so that I can continue playing?" Then see what happens. The DM and Hannah most likely won't be very willing to fix things, so then you simply don't go to the game any more. Then you find or start a new group, possibly with some members of your current group. Move on. The faster the better, that will ease the pain of losing your current PC and forfeiting the campaign.
