Hyouen no Ifreeta: Tsuideni Atashi ga Isekai wo Sukucchau

Asao Rinko plunges into the world of an underground VRMMO to save her brother, Shuuma, who is bedridden in a hospital bed.
Her trump card is the power of "Possession Summoning: Ifrit," which she obtained together with her brother! The enemies that stand in the way, the traps, and the mysteries of the world will all be obliterated by the flames!!
In the world that has at one point ended, Rinko throws herself into battle, clad in the incarnation of fire, in order to save her brother and the people who have been trapped in her heart―――!!

(Source: Gamma Plus, translated)