From A Sacrifice To The Strongest summary:

“I won’t give up!”The moment Kai Takeshi steeled his resolve, he received the skill; .The sudden appearance of dungeon gates, the distortion of common sense. His life, which was equivalent to that of life-stock, has begun to change!He will be blessed with immortality as long as he never gives up with his skill, . He gained another ability, , which he can use to overwhelm the target of his revenge. As long as he has these two abilities and as long as he never gives up, Takeshi will always defeat his opponents.Armed with the abilities that paved his way to becoming the strongest, Takeshi begins his battle!