@Lucky now I understanding some logic here. The system didn't accept the register of skill because he doesn't meet requirements for formless sword which he used before he die he was in his peak both physically and magically condition. But he did have experience of using it but he couldn't use because of lack of magic power and his body couldn't withstand his power. Another theory added is that MC now system is new one than before his dead when all the skill was there. This new system where MC has put and achieved condition for skill getting.
