Energy Saturation
Lin Mu felt the seven elements stirring within him, as the elemental cores seemingly processed them with the help of their respective organs. This was something he had known already as it was common knowledge that the different organs were used for conversion of Attributeless Qi into elemental Qi.
He could sense that the cores were merely drawing them within his body for the initial 'start' but after this he should be able to do them on his own. Now not only could he convert attributeless Qi into elemental Qi through the organs, but he could also use them to directly draw in elemental Qi and store it in the Dantian.
This was exactly what happened, as Lin Mu sensed the seven elemental Qis flowing into his meridians and eventually reaching his Dantian. There, they joined the ocean of Qi, forming different colors sections within it.