Arba seemed to be quite caring when she was first introduced, as she tried to make Sheba feel welcome after the latter was rescued from the tower. She openly expressed her worry when Sheba proclaimed that she wished to go back to her tower. Arba continuously displayed deep and genuine loyalty towards Solomon, always referring to him as "young master," despite the latter's assertion that this was not necessary with her no longer being his servant. She is fearless in battle and refuses to show her enemies mercy.
Arba apparently had a rather impish side too, as seen when she intentionally held back during her training session with Solomon, and cracked jokes with him right after their sparring match, telling him that his swordsmanship "sucked" and that he should grow taller, which caused both of them to laugh.
Arba is also extremely fervent in her belief of Ill Ilah, going as far as to cry and call him father every time she sees him. She was very distraught over Solomon's decision to "kill god" and attacked him in an effort to prevent his plan. After Solomon replaced Ill Ilah as god and she became a Magi, according to Ugo, she started to act strangely. She is now devious, cunning and heartless, as her one goal is to summon Ill Ilah to this world to reduce everything and everyone to nothing.
During the time she possessed Gyokuen, she seems to take pleasure in cutting down her enemies as she laughed gleefully at Kokuhyou Shuu and Seiryuu Ri who were fighting alongside Hakuryuu.