The
back scan for Vol. 1 has really tiny, fairly illegible credits beneath the last track. But given that that track is a vocal theme from Dark Savior that's on other albums, it can't be anything but:
作詞：寺田敏雄 ／ 作曲：近藤洋史 ／ 編曲：松本晃彦 ／ 歌：アン・ルイス
Lyrics: Toshio Terada / Composition: Hiroshi Kondo / Arrangement: Akihiko Matsumoto / Vocals: Ann Lewis
So 近藤洋史/Hiroshi Kondo for Dark Savior is pretty much confirmed.