World's Fastest Level Up (Manga) Vol. 6

Just as Rin completed the Remote Magic Tower, his younger sister, Hana, became embroiled in a life-or-death situation of her own. A unique-skill-stealing killer has targeted Hana for her Stock skill, and he may be even more OP than Rin! Rin is finally able to power up Dungeon Teleportation to the next level, but will it be enough to save Hana?