Could also be a continuity error since i think that Nagi also failed to see him at times. Anothier weird thing is that Sakuya seems to be able to see Father Linn (as seen in one of the chapters where Hayate took Maria to a date) even though she never enter the church
24 is Izumi's brother
13 is Izumi (she did mention that she is the heir of an electric company before they went to Greece)
In order for the manga to end, Hayate's relationship with all the girls, his life as a butler, his 150 million yen debt, the location of Ikusa and the mystery behind the Royal Garden needs to be solve. Intrestingly, when the calender blew to 24th December in the latest chapter which foreshadow the possiblity the end of the series, it is Chrismas Eve, exactly a yr after Hayate met Nagi and Maria's birthday.
I was wondering how the anime is going to adapt to the manga plot. It states that S3 and S4 takes place in Fall which is September-October, after Nagi's doujinshi competition. However, whatever A-tan needs to do to regain her 16 yr old body takes at least 3 months meaning from June to August.
On another topic, the anime needs to get the End of the World Arc and the whole Myokonos and King Midas arc aired, cause based on Hina's upcoming episode, its the volleyball chapter that takes place during Myokonos. Unless, this is a flashback, it will be a problem if Myoknos arc is shown in the anime.