Power Level System Of GCS
The Power Levels of TDG World Known in Glory City are Bronze, Silver, Gold, Black Gold, Legend, With each having 5 stars of separation in their soul power.
The Merged Power Level Currently Shown is,
From Lowest to High:
Bronze Rank 0 Star
Bronze Rank 1 Star
Bronze Rank 2 Star
Bronze Rank 3 Star
Bronze Rank 4 Star
Bronze Rank 5 Star
Breakthrough-->
Silver Rank 1 Star
Silver Rank 2 Star
Silver Rank 3 Star
Silver Rank 4 Star
Silver Rank 5 Star
Breakthrough-->
Gold Rank 1 Star
Gold Rank 2 Star
Gold Rank 3 Star
Gold Rank 4 Star
Gold Rank 5 Star
Breakthrough-->
Black Gold Rank 1 Star
Black Gold Rank 2 Star
Black Gold Rank 3 Star
Black Gold Rank 4 Star
Black Gold Rank 5 Star
Breakthrough-->
Legend Rank 1 Star
Legend Rank 2 Star
Legend Rank 3 Star
Legend Rank 4 Star
Legend Rank 5 Star
Breakthrough-->
Entering the Divine Realm! (Locked Till novel Reaches this stage)
Fighters: They are the people who have reached their current rank, but have not merged themselves with a demon spirit.
Demon Spiritualist: They are the people who have reached their current rank and have merged with a demon spirit beast. Demon Spiritualist has twice the amount of power than fighters when they transform into their demon beasts. Example: Shen Xiu is having a silver ranked 3 power, but her flame Fox demon spirit is gold 1 ranked so after merging he can temporarily use the power of a gold-ranked demon Spiritualist after she transforms and receives the boost in power.
Demon Spirits can be changed with other demon spirits, but resulting in change will erase the existing one.
The God Creation System Currently uses this system to generate power levels, and will only expand once reo starts travelling towards the multiverse.
CREATORS' THOUGHTS 
NoelDragneel
NoelDragneel Power Level System ! Will Keep this updated once a change occurs. So until then you guys can refer this.
Weekly Power Status
-- Power
Ranking 
-- Power
stone