Meiun is a character who introduced in Senran Kagura: Peach Beach Splash and serves as the mastermind and main antagonist of the game.
Little is known of his appearance as he is always shrouded in shadow when we see him.
The event took place on an island separated from all other timelines and in truth the battling between the shinobi students would serve as a ritual to strengthen the barrier to hold off Shin for a little while longer.
However, in truth Meiun was terrified of Shin and did not believe the shinobi could ever defeat him. As such, he planned to use the Peach Beach Splash event to completely cut off the island from all other dimensions by strengthening the shinobi barrier.
And if he was going to forever trap himself on a tropical paradise, why not stock it with tons of beautiful young shinobi while he was at it?
Ultimately, the girls convince him that they will be capable of defeating Shin, and he agrees to let them return home and promises to convert the island into a refuge for people to escape from Shin.
- While technically a "Good" Shinobi, Meiun's plans are somewhat typical of an evil genius: Creation of high tech machinery, manipulation and being hidden in a room clad with screens and other tech.