Some people are theorizing that we'll know Sin's true identity during the next arc, but I don't believe it, the group has been through a lot of sticky situations and definitely the worst was against Ironside, and even then Sin didn't come out, I doubt he will. reveal itself now, maybe not even all the knights in this group together can match Ironside, who looked like a top holy knight, remember these holy knights are young, have little experience, intimidation won't solve anything, maybe they are so obsessed because they know they're weak and want to prove their worth, but anyway that's what I believe, if sin wasn't even against ironside he wouldn't show up against this group. It is much more likely that he will go out to ask for help or do something again, I believe we will only see sin's real identity in Liones, as he is far away from Arthur's troops and there is no longer any reason for him to keep his identity hidden, it is time that we will probably see 3 knights of the apocalypse together, tristan lancelot and percival, furthermore, i wanted to add that, reading the tales about lancelot, it is said that he was considered a sinner, which might fit with the name sin.