Chapter 66: Chapter 66- Awakening Kundalini
Ryuk's POV
'System, heal my body.'
It has been ten hours inside this place since the moment I woke up, leading me to reach the conclusion that the outside world's year was two hours inside.
[ INITIATING HEALING - -⟩ DONE! ]
[ New Ranking: 〖EPIC〗 IMPERFECT ---» 〖EPIC〗 PERFECT ]
[Host, Should I wake you up?]
'Not yet.'
Unlike the beginning where I felt my consciousness dissolving inside this world, now everything seemed like a part of me, a world within my body.
SWISH
The moment I concentrated on *Shunya*, the darkness that was trying to devour me a moment ago started to fade away, replaced by a white glow.
CREATORS' THOUGHTS 
A4KL
A4KL Let me Explain what is happening here~ Ryuk is filling his energy core like balloon and blowing it, not making sense?
Exactly, First his priority was to heal his body, then repair his energy core- System did it with ease.
second, after he awakened Shunya ( which true strength will be revealed in next chapters fight, Yes there will be fight scene in next chap ), he realised that without help of this Immunity which pushed back death to take over him, he would have goner.
meaning his soul was weak.
Now, He get information about the way to awaken his Kundalini ( Spirit Awakening) from an unknown source, it is not big secret, will reveal soon, but important thing is, to awaken his spirit, he needed to reach foundation of his existence which is normal human, but he can't do it while carrying an energy core. So, Using his Null ability which can ~ Nullify, Repel and Immune, any type of energy, he nullified his own energy and let the Spirit to awaken.
-- About Unknown Source, It's not some secret, it was refrenced from Volume 1's last chaps fourth paragraph or exactly when Sword Maiden and Yui do conversation after battleships arrive.
Gifts
-- Gift
received Weekly Power Status
-- Power
Ranking 
-- Power
stone