Isekai Munchkin: HP 1 no Mama de Saikyou Saisoku Dungeon Kouryaku (2018)

宣伝文句
「俺は、この世界のルールの穴を突いて生き延びる――！」
引きこもりゲーマーの高校生・桐原行人は、妹の佐奈を探すため、剣と魔法の異世界《エバーワールド》で冒険の旅をすることに。だが行人には、過酷なファンタジー世界で生き抜くには厳しすぎる、とんでもない「縛り」があって――？

Source: www.anisearch.com/manga/52093

Blurb:
16-year-old Yukito Kirihara lives with his 14-year-old sister Sana, who he treasures more than anyone else. But when an ogre shows up outside of his window looking for Sana (a shocking event in its own right), Yukito leaps to save her – and is killed. He’s offered the promise of reincarnation by a mysterious woman, who gives him a character sheet in a mysterious book. But when Yukito sees Sana in there, too, he sets off to find her, and save them both – even if he only has 1 hp with which to do it!

Source: www.anisearch.com/manga/52093