Kayle and Morgana are the children of the Aspect of Justice because Riot wanted to explore the idea of children of Aspects.
Riot moved away, narratively, from Kayle and Morgana stemming from a race of angels due to angels having certain cultural connotations that would be harder to expand upon as Riot moves the narrative setting forward.
Riot decided to only partially update Morgana's kit during her Visual Gameplay Update due to her having a timeless kit that was consistently healthy throughout the years.
Several scrapped spells tested for Morgana include:
A version of her passive that would grant her bonus movement speed towards enemies, 100% spellvamp and expel waves of true damage damage for 6 seconds once she dropped below 30% maximum health.
A version of her passive that would grant her bonus movement towards enemies she had damaged or her allies had crowd controlled.
A version of her passive that would grant her bonus auto attack range towards enemies she had snared.
A version of her ultimate that allow to her ascend with ranks like Kayle and would give her bonuses including bonus movement speed, spellvamp and true damage.
A version of Tormented Soil that would critically strike against low health targets.
Kayle and Morgana are both ascended hosts of the Aspect of Justice. They share the power of the aspect due to their mother, who was the former ascended host of the aspect, being pregnant with them during her ascension. Both sisters retained some essence from both their ascended mother and the aspect during their early years.
Morgana and Kayle currently have less celestial power than the other Aspects due to being the children of an Aspect but have free will and a more unified identity.
Morgana and Kayle became ascended when their wings materialized shortly after their mother's swords fell from the heavens.
Morgana's wings break free from their bonds when she uses Soul Shackles and she surrenders herself to her celestial powers.
Morgana rejects her celestial heritage and in turn her magic has become twisted and corrupt.
Morgana currently resides in the outlying wilds of Demacia and rectifies wrongs she sees fit on an interpersonal level as the Veiled One.
Morgana's view on justice is more nuanced then Kayle's as she cares more about the intent of why someone would commit a crime. She believes criminals deserve to feel the pain and suffering they have inflicted in order to truly reform, redeem themselves and feel empathy for others.
The way Demacia views the Veiled Lady has changed over the years, some see her has a figure of punishment and others see her as a figure of judgement.
Variations of the Season 2019 Split 1 emotes are given to players who play enough ranked to obtain 500 Split Poins. This emote was the first appearance of the reworked Victorious Morgana months before the champion's update reveal.