Valkyrie

Dr. Jane Foster is an ally and friend of Thor Odinson's. When Thor became unworthy, Jane took up the mantle as the Goddess of Thunder to protect the ten realms in his absence; despite having her own personal battle against cancer. Jane eventually convinced Odinson to reclaim his name and continue fighting the War of the Realms on her behalf, so that she could focus on her chemotherapy treatment. 

Following the War of the Realms, Jane was approached by the spirits of the fallen Valkyrie. They presented her with an opportunity to honor their memory and guide lost souls to Valhalla by becoming a Valkyrie, to which she accepted.