Original run

The original run of Heartcore started on May 5, 2009, and ended four years later on May 9, 2013. TL Welker expressed dissatisfaction with the artwork of the original run's early pages and wished to improve upon the story. This started with an improved version of the opening scene from Chapter 1, "Sinful Rose", with the reboot starting in earnest on June 21, 2013.

Many changes were made between the original and current runs, as listed below.

Sukina Lashiec
Sukina was originally based on a character created by an acquaintence of Welker. Welker grew dissatisfied with the character's depiction, describing her personality as "milquetoast". The current run's version of Sukina, while still delicate, is also shown to be curt and sharp-witted, as well as an actively supportive character: while the original run's version of Sukina was mainly a damsel-in-distress, the current run's version aided Amethyst in combat, from attempting to attack Slade with a skillet to summoning the bauble demons, Rip & Tear, to aid Ame.

The current run's version of Sukina is also more visually distinct, largely because Welker wished to make the character more distinct from its original source of inspiration: while she retains her blue eyes, her hair is changed from pink to lavender. Her outfit was also changed, being darker and more in line with the fashion worn by the demons of Asgar as opposed to the white dress of her original design.

Goristro Austerlitz
Goristro's character design may have been given the largest overhaul of all the characters in the current run, with his black downward-curving horns (not pictured) replaced with curving goat-like horns, and his headband replaced with chin-hair and distinct facial markings. He was also given a slightly darker skin tone and a more burly build.

Royce Lashiec
Royce had a more youthful character design in his old run design, along with golden horns. His new design gives him a more mature, adult appearance, in addition to making his hair a darker shade of red, and his horns as black as his heart.