Itsuka Tenma no Kuro Usagi (A Dark Rabbit Has Seven Lives) is a 12-episode TV series that aired in 2011, following the airing of LotLH in 2010.
A 13th OVA episode was released with the 9th volume of its manga on December 11, 2011, with 3 short stories. It was titled いつか天魔の黒ウサギ
The third short story involved a crossover with characters from The Legend of the Legendary Heroes.