Huh... now I have questions. First of all, is Hnaef calling Arthur his boss (almost certainly), or is he referring to someone else? Arthur & Mordred's father perhaps, maybe Sedrick... though he'd probably refer to Sedrick as "Dad", so probably not him.

Secondly, Hnaef specifically said that Arthur doesn't know about the sister. So I'm wondering if anyone else in the family does and finds it similarly funny that Arthur doesn't know. Maybe one of their parents, or Janus, who we haven't been introduced to even though they've been name-dropped.

...You know what? I'm going to say that everyone in the Garrott family but Mordred and Arthur knows about Wiglaf's Sister. Mordred doesn't know because they were keeping it from Arthur as a family-in-joke and there was never an opportunity to tell him, and Arthur doesn't know because he only paid attention to Wiglaf himself and not any attachés, allowing the in-joke to develop naturally.

Wiglaf just had to ask at the "Perfect" time and it went well

W I G L A F
oh my god.

They say it's better to ask for forgiveness than permission . . . Which one does this really count as?