Gao Wu: I Survive by Killing Monsters

In the last five days of his life, Lu Chengchuan received a krypton life system. As long as he spends his life inside, he will become stronger and stronger, but of what use is this to him? It is tantamount to giving a golden rice bowl to a beggar. Until monsters appear and he discovers that killing monsters can gain life... (No heroine, no harem.)