In the opening jousting sequence, Deathstalker has an English accent which is not heard for the rest of the film.
Although the opening scene takes place in the "North" of this country and Troxartas's castle is in the "South," where Deathstalker had to travel by boat, Marinda, who is from the South and had never left her home prior to meeting Deathstalker, is somehow able to find her way north, locate the people from the opening scene, and bring them back south to the battle in about 15 minutes.
When Nicias appears inside the castle and Troxartas' men take him away, his hunchback shifts noticeably under his cloak, revealing that it's just padding.