Other Appearances
As Tales of Phantasia was the first Tales game, it also makes the most cameo appearances in other Tales games. A few of these re-imaginings of Chester are actually quite interesting, whether they be canon or fanservice.
Tales of Eternia
In Tales of Eternia, Chester is a spectator in the arena when Reid Hershel, the game's main protagonist, faces off against Cress (and if certain conditions are met, Arche) in a special match.
Tales of Phantasia: Narikiri Dungeon
In this Japan-only release sequel of Tales of Phantasia for the Game Boy Color, Chester makes an appearance and what happens to him after the events of Tales of Phantasia are revealed. What happens to Chester is that he begins running an orphanage, under the reasoning that if he can take care of orphans and raise them in a caring manner, they won't grow up turning to an immoral lifestyle and blaming others for their own situation. It is hinted that he considers himself much like that, and so he attempts to prevent others from having to go through the same thing that he himself went through.
Later on, when the game's main protagonists (Mel and Dio) are experiencing an obligatory epiphany, the issue of Chester's motives are brought up: is he running an orphanage for the children, or for himself? This is an interetsing question, because the game brings up questions of motived for a lot of people; in fact, all of the characters in Phantasia have their own vices. In fact, all of humanity have their own vices; human nature isn't innately good. The main message here is that because we have inherently bad natures, it means all the more when we intentionally fight against it to do good. Even if motives may never be completely pure, a hint of kindness goes a long way.
Tales of the World: Radiant Mythology
In this incarnation, Chester and Arche are basically alone as the sole representatives of the Phantasia cast. Cress is nowhere to be seen, and it's made apparent that Toltus was already decimated as the anniversary of Chester's parents and sister's deaths were mentioned in the game.
What's interesting is how Chester pays a role in the overall story of Radiant Mythology, by sort of adopting Kannono (one of Radiant Mythology's exclusive characters) as a replacement for Ami. Granted, the way he goes about it is more than creepy even by my standards, and even makes Kannono feel uncomfortable as well as making Arche talk smack about Chester behind his back. Eventually, however, he backs off and matures a little bit as a character. If anything, it's an interesting alternate-universe interpretation of his character.
Another interesting thing about this game is that Chester's and Arche's relationship is more blatant than the other representations, where Arche show more of an obvious attractions towards Chester.