This main title(yellow words) is not Japanese. Jeisan has already said, "that just looks like its just a stylized writing of the word 'rai'". It's a right! It's a design for the main title "RAI" and is stylized as a Kanji. This word does not have any meaning in Japanese.
The first word of main title is a original picture. It's not in Japanese. The second word of main title is "太". This meaning is a "thick". The third word of main title is a original picture. It's not in Japanese. But it looks like a Kanji "工".
What mean white word "霊"? This Kanji is "Rei" in Japanese and means "soul", "spirit" and "ghost". I think that this book's title "RAI" origin in this word "Rei". Because Japanese "Rei" is pronounced "Rai" in English and English "Rai" is written "Rei" in Japanese. For example, "rain". "Rain" is written "Rein" in Japanese. This book's title is mistake in the strict sense of the word. The correct title is "REI" in Japanese but not "Rai".
By the way, "霊" is "ling" in Chinese.
Yes, you find out a good point. "Rei" is a one word now, but this word is made of two words originally.
The upper part Kanji is a "Ame" and means "rain" in English. But this Kanji is an abbreviation and is "Rei" originally. This "Rei" is different from "Rei" that means "spirit". This original "Rei" means
the advent of a god(but it means "descent" in literal translation).
And bottom part Kanji is an abbreviation and is "Miko" originally. "Miko" means "shrine maiden" in English.
The first(white) word "Rei" express a shrine maiden with the advent of a god on her overhead.
In Japan, people had believed that shrine maiden can be possessed by a elemental spirit. "Elemental spirit" is synonymous with "god" in Japan. And shrine maiden told god's intention. It's similar to the Delphic oracle in Europe.
"Elemental spirit" is "Sei-rei" in Japanese and Japanese shrine maiden conceive a "god". In the West, the Virgin Mary conceive a Christ by the Holy Spirit. And "the Holy Spirit" is "Sei-rei" in Japanese.
But "the Holy Spirit" is used different Kanji from "Elemental spirit".