Another AU I think it's called or headcanon.
Where before the Baron was an outcast and a traitor to the kingdom he was Sir Gareth's student(mentee?)
Gareth and Baron are the only two Knights who know the protocol of by heart so this is why I figured it would make sense if Gareth is the reason why the Baron also knows it of by heart.
As for swordsman skills, Gareth and Baron both have a habbit of bragging about there fighting skills against Alex but of course Alex always wins against them both. So that's a similarity.
Baron doesn't really touch people genuinely and casually often, he's only done that to Rypan once who is a close ally and his right hand man. So for him to act the same towards Gareth body language wise I'm taking that as they used to be freinds but when Gareth pushed him away it's a clear answer that he doesn't consider Baron a freind anymore regardless if they used to get along.Gareth Said he doesn't trust the Baron and Barons face turns into shock then sad/angry at his words.I added the Rypan and Baron gif as it shows instead of Baron being pushed away like how he did when he touched Gareth, Rypan accepts it and because of that Baron pulls him closer. This solidifies there bond and freindship.
Sir Gareth at times is suspicious of Alex and his freinds, expecting them to do smth bad or break his and the kingdoms trust. This could stem from Baron betraying him and the kingdom in the past and now he's more cautious where to place his trust all thanks to Baron.
When Alex almost didn't show up to fight the Baron, Gareth was quick to offer. In the past in my AU they would fight and train together, both being competive so this could of been a chance for Gareth to fight Baron just like the old times.
That's how I see them anyways.