Donten ni Warau Vol 3

From the Tokyopop edition

Soramaru's quest to grow stronger brings him to the leader of the Yamainu, Abe no Sousei.� Sousei proposes a trade: training in exchange for information.� In search of the information required, Soramaru disguises himself and — with the help of youngest brother Chutaro�—�infiltrates the very prison he's taken so many criminals to: Gokumonjo.� But nothing is ever as easy as it seems, and although Soramaru finds the information he needs to make a deal, eldest Kumo brother Tenka suddenly finds himself under arrest and in dire straits...

Source: Anime News Network Encyclopedia