During his discussion with Beatrice, Roswaal wore his typical jester's outfit, while in the Light Novel, he donned a primarily black aristocratic outfit–the same as the one Roswaal A Mathers was wearing during the Sanctuary flashback.
Roswaal's apology did not happen off-screen, like it did in the Light Novel.
The dialogue between Beatrice and Subaru after their fight with the Oousagi was entirely omitted. Hence, Beatrice did not tell Subaru that she has burned through her entire mana reserves, making it impossible for her to use any kind of magic save for the most basic spells.
Subaru and Roswaal's conversation is shifted from after the Knighting Ceremony, to before it. The location has also been shifted from the ballcony to the great hall.
A significant amount of plot points have been streamlined, brushed over or changed. Roswaal did not state that he was not Meili's contractor.
In the anime, Roswaal states that losing someone dear to him will result in him killing everyone, however, in the Light Novel, he states that if Subaru loses someone dear to him, Roswaal will not hesitate to kill everyone dear to Subaru and force him to restart.
During the Knighting Ceremony, Roswaal makes his appearance in his archetypal jester outfit, while in the Light Novel, he can be seen sporting a primarily black aristocratic outfit–the same as the one he wore during his discussion with Beatrice.
A short scene with Annerose Miload inviting Natsuki Subaru to the altar was added.
Clind and Annerose's short quarrel has been omitted.
The final Arc 4 scene with Echidna emerging from the Sanctuary after successfully hijacking Shima's body and naming herself Omega was entirely omitted.