Going back even farther, one of Ash's win quotes in 2003 was "Don't play your trump card till the end... the very end!" In hindsight, SNK was pretty much telling us, "Keep your eye on this guy. Something's gonna happen." - X2X
Related to the above: In XIII, Ash's a single entry character. Quite odd, given that he's The Hero of the saga... You'd think that it's because he'll become the True Final Boss at the end as Evil Ash, and that's right - but it's deeper than that: Like the above Troper has stated, he's prone to manipulate his teammates to his own ends. So him being a single entry is a subtle Gameplay and Story Integration - He can make team with any character in the roster, but he'll end up leaving them in the end.
There are three people that are able to sense that Ash's intentions aren't as malevolent as they seem. One of them is King, who refers to Ash's behavior as "a cry for help" among other things. Why would she sense such stuff, considering that she's not a psychic (unlike Athena) and has relatively limited experience (unlike Chin)? Easy: she's a bartender, and bartenders are typically used to listen to the problems of people who are drowning their sorrows. This means she can catch body language signals that others cannot, whether the person she's speaking to is toasted or not; then, it's not surprising that she can see that Ash's plans and mindset are more complex than he lets other see, even when she obviously doesn't know what he wants (and never will, now that he's gone forever). - Orihime
For some people, Yuri's Neomax, the Haoh Raiouken, seems lackluster compared to flashier Neomaxes, save for the mushroom cloud at the end. Then, I realized that, unlike fellow Kyokugen practitioners Ryo and Robert, she was only taught the very basics of Kyokugenryu, aptly named the Raiou principle. In a way, her Neomax serves as a Take That to her father and brother, showing that she can throw away Raioukens like atomic bombs. - Aenthin
Also, when you examine Yuri and Ryo's relationship, some interesting conclusions can be deduced/speculated. Ryo is the dutiful son, the one trained from childhood by his father Takuma to become the heir of Kyokugenryu, alongside his natural talent; Yuri is a late-bloomer, who only started when she was a teenager and mastered the basics within a year. While they love each other dearly, they also intensely clash: Ryo objected to her being trained (though he doesn't object to otherAction Girls being around, like King or Mai), Yuri decided to keep training and then add her own variations to the style. Ryo's current objections to have her around don't only come from her being a girl (though that does play a part), but because he sees Yuri's additions to the Kyokugenryu roster as an insult to the Kyokugenryu style itself... and also as a part of their interactions outside the ring. Ryo had to work very hard for his martial arts skills and to make the Kyokugenryu style widely known ever since he was a young boy, adding an It's Personal layer to what seems to be a mere "Stayin The Kitchen"-like Sibling Rivalry, even when it's not very fair to Yuri herself - Orihime