A decent amount, he supposes

Tsukane found a book on various monster species and started reading. "Incubi, incubi... 'The male version of a Succubus. For more information, look under Succubus'... Seriously?" Tsukane grumbled before looking further in. "Succubus, succubus... Ah. 'A monster of the night known since the middle ages. The female version of an Incubus, it appears in the dreams of sleeping men to seduce them.' So, I could possibly enter dreams." He pondered before he resumed his reading.

" 'Succubi are "creatures of love" and, as such, gain power from their loved ones and their "Mate of Destiny". If they are not loved by their Mate of Destiny, the Succubus will eventually die.' Yikes... I should probably keep that in mind with Kurumu... 'Appearance: Succubus's true appearance isn't very different from the appearance of a Human. The only factors that set them apart are the growth of long nails, bat-like wings, thin and long grey tails, and gaining pointed ears.'" Tsukane reached a hand up to his ears... and sure enough, he could make them pointed! "Neat! not sure that part would be helpful.... Ah, Powers and abilities!"

'The following list is a list of all known powers and abilities that Succubi are known to possess.

• Flight: With their wings, Succubi can take to the skies and fly. They can even carry other people, though their strength limits their carrying capacities
• Enchanted Kiss: A succubus's kiss is known for having unique properties. Their kiss can enslave their chosen target to their whims forever. It is also said to steadily drains away their life-**** killing them slowly with repeated use.
• Strength: Succubi have been shown to be able to cut apart trees as if they were butter with their claws, suggesting that they have great strength, though not comparable to most stronger species.
• Charm/Allure: By looking into a man's eyes, Succubi have the power to hypnotize that man and control him as if he were a marionette.
• Illusions: Powerful Succubi can gain the ability to cast powerful illusions, which seem to possess some physical effect.
• Mind Entering: Succubi have the ability to enter another person's dream with their tails. To do this, the end of their tail opens like a flower which they then put on the intended target's head before entering the person's mind.

"That's a useful summary to know, but not sure if that's everything. Wait... 'Chest Laser'? Mature succubi can fire beams from their boobs? That sounds a bit dubious." He shook his head at how silly that sounded... though glowing boobs could be funny, he admitted to himself. "Anything here on incubi... Ah, a footnote. 'Given that incubi have been considered effectively extinct for centuries, differences between them and succubi are unclear.'... well, that was a lot less than I was hoping for... still, I at least found a decent reference book for species around here." Tsukane picked up the book and put it under his arm, walking over to the front desk to check it out.