-circle-eden-mayuri-sama-no-jintai-jikkenshitsu-5.5--bleach-l.pdf Site

It sounds like you're referring to a fan-made or derivative work title, possibly related to Bleach (given "Mayuri-sama" and "Jintai Jikkenshitsu" — "Human Experimentation Lab") and a "-Circle-Eden-" doujinshi or fanzine naming convention. The "5.5" suggests it might be an extra or side chapter to a series.