Ojousama-kei Teihen Dungeon Haishinsha, Meiwaku-kei o Bokottara Bazutte Densetsu ni Nattemasu wa!? - Ch. 16

[CypherHoof]

Man, I gotta speak to the author. What's the point of making her an orphan?
Do whatever you want, just give me a good reason why.

Well, apparently coping with the grief and loneliness is the reason she became obscessed with Dungeon Alive! and Lady Setsuna.

Also if she had competent guardians, they wouldn't have let her wander around a dungeon with no armour, no weapon, and come home with bleeding fists because it is cheaper to heal than replacing a sword.