Asuna's reason for having a bodyguard was something Feng Chen more or less knew. In SAO, Asuna was among the top players based on looks alone, let alone her powerful abilities.
She was practically an idol in the hearts of every SAO player, wasn't she? A player like her would easily attract the attention of people with ulterior motives when she went out into the wilderness, which was why Heathcliff had arranged a bodyguard for her. However, Heathcliff, who knew little about guild affairs, also knew very little about Kratier.
(From Heathcliff's... no. From your perspective, I would have no hesitation in saying that assigning Kratier as Asuna's bodyguard was a mistake.)
The reason was simple. It was one thing that Heathcliff knew nothing about guild affairs, but he didn't know the players well, either. He had only seen Kratier a few times during regular meetings before making him Asuna's bodyguard—it was simply too hasty.
Among all the female players in SAO, Asuna's strength ranked in the top three. Why not say she was number one? Mainly because of Bella. Bella had never fully displayed her strength. The only time players had seen Bella fight was during the strategy operation against the Floor Guardian BOSS on Floor 50. Under any other circumstances, Bella wouldn't even fight.
There was another reason: Feng Chen spoiled Bella too much. When they were leveling, Feng Chen could definitely kill monsters faster than Bella, so he often did things that angered her. Namely, stealing Bella's monsters, then desperately trying to coax her out of her anger.
"If the reason Master parties with me is to steal my monsters and then let me gain experience without doing any work, then please don't party with me. Bella doesn't want to gain anything without working for it, and