SEGA Networks Japan will be releasing a Valentine’s Day SEGA Hard Girls collab for Chain Chronicle V (the PS Vita version of the game) in Japan. The collab event will be available from February 8th 2016 until the 16th in which you can get / unlock Dreamcast, SEGA Saturn, and Mega Drive Hard Girls with a special Valentine’s Day costumes and Chocolate love weapons.
If you have your PS Vita linked to a Japanese PSN account you can download Chain Chronicle V from the J-PSN store or if you have the physical version of the game you can link it to a J-PSN account and get them on this special event.