
As we learn in Book 5, Epel is only being forced to adhere to Vil’s rules until he is strong enough to win against Vil in a fight.

This is referenced in several of Epel’s lines in the original game where he talks about beating Vil, but all of Epel’s references to wanting to beat his housewarden have been changed in the English-language adaptation to wanting to beat Crowley, instead.

Epel’s misogyny was downplayed for the English-speaking audience:

Original Epel: Ah sure don’t want no part of a dorm run by a feeble, girly guy like this.
EN Epel: Ah sure don’t want no part of a dorm run by a prim ‘n proper gent like this.

Original Epel: What did you just say? That I’m feeble like a woman?
EN Epel: Win-what? You callin’ me a wuss?

Original Epel: You’re feeble an girly, too!
EN Epel: Well, if Ah’m a pot, yer a kettle!

Original Epel: Daaang…when I think about Rook-san being able to use it, that becomes some mighty scary magic…
EN Epel: Daaang…that’s a mighty scary piece o’ magic.

Original Rook: Speaking of Spelldrive…I’m told that even Leona-kun holds Epel-kun’s flying prowess in high regard.
EN Rook: Speaking of Spelldrive…I’m told that Epel’s flying prowess is even greater than Leona’s.

In Rook’s original dialogue, he follows up Vil’s praise of Epel’s accuracy with his magic by saying, “Speaking of Spelldrive, I’m told that even Leona-kun holds Epel-kun’s flying prowess in high regard.” This is a reference to an earlier conversation in Book 6, where Epel himself tells Rook that Leona has said that he is the best first-year flier in the Spelldrive Club.
There seems to have been some confusion on EN, with Rook’s line mistranslated as, “I’m told that Epel’s flying prowess is even greater than Leona’s,” which is not the case.

During Halloween Epel says, “tange, meh!” while describing pumpkin pudding. This is an expression from the Tsugaru dialect of Japan’s Aomori prefecture and just means, “really delicious.”

In the English language adaptation of the game, Epel’s line has been changed to, “It made me want to slap my mama.” Since there can really be no equivalent to certain dialects across languages, it makes sense that Epel’s phrasing is being changed for EN.
But if you’re wondering if “slap my mama” is an expression that was translated directly, it is not.

(While Epel repeatedly uses the word “tange” for emphasis of when something is delicious/cool/fun, the “slap my mama” localization has only appeared the one time.)

After seeing Epel’s delight in riding a blastcycle Vil decides to assign him the main role in his student film, leading to Epel being dragged away by film club students while protesting.

At this point in the original game Vil says, “Does the light in one’s eyes really change so completely depending upon if they’re doing something they have an interest in or not? What a troublesome apple.”

This was changed in his English-language dialogue to, “And yet his eyes clearly lit up at the prospect. I see right through you, my dear Epel.”
This may be a misinterpretation of Vil’s original dialogue, which means the opposite: Epel does not have any interest in the film, only in the blastcycle, and his eyes are not lighting up at the prospect of the role. The light has gone out because his excitement for the blastcycle is gone.