Black Lagoon OVA Roberta’s Blood Trail OP Direct from Nico Nico
Sound Version only: http://nicosound.anyap.info/sound/sm11199221
Nico Nico Source: http://www.nicovideo.jp/watch/sm11199221 (Account Required)
Copyright goes to Madhouse + Rei Hiroe and all the fine men and women who created this great Anime.