First appearance: Odin Sphere (オーディンスフィア, Ōdin Sufia), released in 2007.
Creator: George Kamitami
Weapon/ability: Spear and psyphers
Gwendolyn is one of the five main characters in the video-game 'Odin Sphere'. She is the younger daughter to the demon lord Odin and the one who has to lead the Valkyries in battle after the death of her older sister, Griselda. She is willing to do just anything to gain love and recognition from her father - but he spends most of the time ignoring her, or just using her.
When she tries to do the right thing and prevent the execution of her half-sister Velvet, he ends up putting a spell on her and marry her off to a stranger and enemy to the Valkyries, an ally of the fairies - Oswald, the Shadow Knight.
But even after she is married and has left her home her loyalties are tried on several occasions when her father still expects her to act as his daughter - even when it would mean betraying her husband - and at the same time battle the feelings she starts to develop for Oswald, which in the end results in her taking her spear to save his life when he gives up his will to live and is dragged down to the Netherworld.
Gwendolyn and the characters around her are obviously inspired by Norse mythology - but very, very loosely.