Summoning Only Skeletons is Too Strong

Introduction to the Work: Earth destroyed by an invasion from another dimension. Lee Han, possessing the mythic trait [Undying Lord], regresses from the end of the apocalypse. With the goal of monopolizing hidden achievements and obtaining mythic traits to exact revenge. [Achievement ‘Gotta Get Those Skull Materials Yourself!’ acquired.] [Trait ‘Skull Expert (Common)’ acquired.] [Unique Skill ‘Skull Creation’ acquired.] But Lee Han, being too exceptional, achieves excessively unexpected achievements too quickly. Suddenly becoming a skeleton summoner… but it was too early to despair. The unstoppable growth of Lee Han, a summoner with exceptionally special skeletons who is also good a...