My favorite bit about the Royal Guard is how they each have their own idea of what it means to serve the King
Pitou - Sees Meruem as an individual but also as King, very loyal to Meruem and the Ants but is more accepting of his "changes"
Youpi - Sees Meruem as the King, his leader. Not really willing to put more thought into it, focused on his job as a Guard. A middle ground between Pitou and Pouf
Pouf - Sees Meruem as the Supreme Ruler and The King of Ants, but more as an idea/title than an individual, unaccepting of Komugi's influence.
Pouf is a shitty jackass, but he is a good character. He never really compromises his idea of what he believes Meruem to be, even if he knows he's betraying Meruem the individual. Pitou on the other hand eventually goes along with what Meruem wishes, even though Pitou knows it isn't right for the Ant King to do something like that (i.e.
).
Youpi just doesn't care what the King does as long as the King is safe and ruling, of course he discovers his own individuality besides it, but it doesn't change his views of the King.
tldr I love the Royal Guard and I love that their singular devotion to one being manifests in such different ways