For me, the 8 tails passive is super useful
But yeah, keep a list of it and have challenge clarification of host/summoner for me fine. It's really just a matter of keeping things 'pretty'.
As long as Athos complies to the rule, ie makes sure to mention he's the summoner in his challenger rule agreement threads within a week of officially starting each challenge/isn't actively acting out of spite against the rule there should be no issues.
For now, we should just give him a nice reminder, if Athos clears things up we leave it there, if he does it again, a warning, if he doesn't comply then/continues to put 'host' instead of 'summoner' in his threads like a month or two we move for an appropriate punishment of sorts but only if he actively denies the rule, refuses to adhere to it, etc. This should go for everyone. We all follow the rules which the community has agreed/voted upon. Some we like, some we don't like, but if we want to continue to participate, we must adhere.