Tu Bian Yingxiong LEAF

Yuye Hua is a clever high school girl. One day, she is suddenly sucked into another world. This dark world is a world without light and the inhabitants are only children wearing panties. Arriving there, Yueye is the only one wearing clothes and she will become the heroine of this world where clothes are the strongest weapons.
(Source: Anime News Network)
Note: This entry reflects the original 12 episode Chinese broadcast version, the Japanese broadcast version was recut to condense the original 12 episodes into 7x24 minute episodes and aired from 19.05.2018 till 07.07.2018.