I recommend the following two novels to you. Both of them meet the requirements of the male protagonist to keep a low profile and hide his strength very well. "Douluo: My Strength Was Almost Exposed". After the male protagonist crossed over to Douluo Continent, he activated the hidden strength system. As long as he hid it well, he would be able to obtain generous rewards. From then on, a hidden king appeared on Douluo Continent. "Time Travel: Clinging to the Male Lead's Leg". After the male lead transmigrated, he obtained a powerful system. However, he accidentally discovered that he was not the only one who transmigrated. There was also an even more powerful system. Therefore, he decided to form an alliance to fight against the system and reach the peak of the human world. At the same time, he wanted to cling to the thigh of the standard male lead. I hope you like my recommendation. Muah ~