In the comments of one of his blog posts, a fan asked akiropito what the composer credits where for Rondo of Blood.
http://akiropito.blog.shinobi.jp/その他/あけおめことよろ#comment3
This was back when his blog was active, so he answered. The credits in the words of akiropito are as follows:
"・Cross a Fear, Cemetery, Slash, 幽霊船の絵, Op.13, 巣窟, 聖者の行進, は地獄車中村さんの担当です。
・鎮魂歌, 獄幻界乱舞, 幻想的舞曲, Mary Samba, ボス戦前の曲, その他デモシーンの曲はSannopiさんの担当です。
・ボス戦前の曲,ジングル, Poison Mindのアレンジと乾坤の血族(Overture)、擬音(SoundEffect)は私が担当しました 。 "
That leaves us with complete credits for the OST! I've updated the KICA-7622~3 release of the soundtrack to reflect this.