I am here to help you as I am also struggling with some cool features that I am not sure how they are working I usually find it out really luckily. For horn it seems that you can use it in fight when there is "space" for reinforcments you can right click with the horn and your character will blow it. In the chat log there will appear a blue text stating that reinforcments have arrived (normally the text is white). I am not sure how it works, what kind of troops will arive etc. but at least it is cool xd. Also it is possible to repair and upgrade your horn but I am not sure if it makes any difference. If there is something you dont understand just text me but hopefully I've explained that well.

Originally posted by Shirokeey ♥♥♥♥♥♥♥♥♥.com:

I am here to help you as I am also struggling with some cool features that I am not sure how they are working I usually find it out really luckily. For horn it seems that you can use it in fight when there is "space" for reinforcments you can right click with the horn and your character will blow it. In the chat log there will appear a blue text stating that reinforcments have arrived (normally the text is white). I am not sure how it works, what kind of troops will arive etc. but at least it is cool xd. Also it is possible to repair and upgrade your horn but I am not sure if it makes any difference. If there is something you dont understand just text me but hopefully I've explained that well.

Thanks for your answer :) and about upgrading items i tried to upgrade that horn to "Hornis" but after waiting about 6 days i got my normal horn back.But when i tried to upgrade my sword it worked.Dunno if its just got bugged or something.