To celebrate the start of the televised anime series Black Butler: Public School Arc, Square Enix will make several chapters of the English translation of Black Butler, the original manga on which the anime is based upon, available free of charge for a limited time on the global version of its Manga Up! manga reading app.
Volumes 1 through 14 of the manga can be read for free from until April 16th (7:59 PM PDT).
In addition, a new subscription plan called VAULT PASS was introduced. For a flat rate of $4.99 per month, the VAULT PASS unlocks more than 10,000 chapters that previously required a wait time or individual payment. With this service several completed series (such as Scum's Wish) will offer unlimited reading on all chapters.
18 volumes of Black Butler will also be available with VAULT PASS along with the company having plans to make a portion of future installments available via the plan as well.
A selection of available titles under VAULT PASS:
The Apothecary Diaries (chapters 1-54)
My Happy Marriage (chapters 1-27)
The Case Study of Vanitas (Memoire 1-1 - Memoire 61-5)
Toilet-Bound Hanako-kun (Chapter 1-1 - Chapter 111-2)
Source: Press Kit