Your ESP'er Rank is found on upper screen of the save screen. It is a title/rank, which can only be changed by raising the amount of ESP'er Points a player has. When you first begin a new game, your ESP'er Rank will be "Only Human".
The ESP'er Ranks, their grade and their points requirement in the North American and European versions:
Demon: ★ (10001 - 65535 ESP'er Points)
God: ★ (10000 ESP'er Points) (NA/EU Version)
Demon: A (7000 - 9999 ESP'er Points)
Angel: A (5000 - 6999 ESP'er Points)
Fallen Angel: A (3000 - 4999 ESP'er Points)
Composer: B (2000 - 2999 ESP'er Points)
Conductor: B (1000 - 1999 ESP'er Points)
Reaper: C (500 - 999 ESP'er Points)
Master Player: C (300 - 499 ESP'er Points)
Supernatural: D (200 - 299 ESP'er Points)
Spoon-bender: E (100 - 199 ESP'er Points)
Only Human: E (0 - 99 ESP'er Points)
- It should be noted that the God rank, available at exactly 10,000 points only in the US and EU versions, is thought to be a programming glitch, which occurred after they lowered the point requirements. The God Rank used to be obtained at exactly 65535 Points in the Japanese version, which is the maximum obtainable value.