So I just stumbled into this dead end myself and am bumping this rather than making a new thread, has there been any new information on Mayu's whereabouts? Or was he successfully smuggled out of show business along with Klaha?
As far as I know he just wandered off and never came back. What's in this thread is the last I ever heard.
He's working with Azusa Kobayashi. She just put out an album where he played guitar and wrote music for it, along with performed in a concert last year.
http://visualkei.wikia.com/wiki/MAYU
https://www.amazon.co.jp/Blue-光と闇の中で-小林梓/dp/B01N7YPY6M
In Japanese, here's Google machine translation of the product description
Product description
Introduction
The first concert album to be released is a complete song by MAYU, a guitarist of LAREINE (Laraine).
In addition, LAREINE's bassist EMIRU will participate as a comprehensive producer.
Unlike songs of Azusa Kobayashi so far, the number that injures the visual lineage of the 90s is the core.
Her new challenge and world are drawn, and it is expected work for its versatile expression power.
Media review review others
This is the first concept album this work offers full music by MAYU which is guitarist of LAREINE (Laraine). In addition, EMIRU which is the base of LAREINE participates as a comprehensive producer. Unlike songs by Azusa Kobayashi so far, the number reminiscent of the 1990s visual lineage is the core. Her new challenge and world are drawn, and it is expected work for its versatile expression power. (C) RS
*another mystery solved*
check video at 1:19
Or just watch all of this one
Now if I could only find Klaha...