i'm a player that's recently used 'ser' as a title, but i did it because of what the other anon said, i had no idea what to call them and while 'my lord' and 'ser' are actually appropriate, until there's actual introduction or whatnot, i err on the side of caution. a character that doesn't know another character using 'ser' or 'my lord' should be corrected, like most non-knights do when they're addressed as 'ser' or 'my lord' in the series. if my character isn't corrected in a thread, my character won't stop calling them that.