Magica marks the return of guitarist Craig Goldy, who also has performed on Dio's album Dream Evil and in the later release Master of the Moon. Magica also features Jimmy Bain on bass and Simon Wright on drums. Band leader Ronnie James Dio produced this concept album. The album was originally planned to be the first part of a trilogy of concept albums, and shortly before beginning his tour with Heaven & Hell, Dio announced his intention to start the Magica II & III album after the tour's end, but he died shortly after of stomach cancer on May 16, 2010. The only song released from Magica II & III was titled "Electra".
Said Dio: "Magica is the saga of Blessing, a netherworld invaded by dark forces that vaporise people into pure, evil energy. The planet’s saviours are master, apprentice heroes Eriel and Challis, who must recite a spell from the sacred book of Magica to defeat their foe, Shadowcast. The album is written from the villain’s viewpoint. (...) I took on the evil perspective because I’ve always written from the anti-perspective. Most people don’t think in those terms so you are freer to create. I left the ending ambivalent because evil always exists, good doesn’t always triumph and that’s the universal balance." 
A 2007 re-release puts Magica together with Killing the Dragon.
Dio guitarist Craig Goldy stated in an interview "We were working on tracks for a new DIO album just before Ronnie died in May. And we did almost finish one song. Wendy [Dio, Ronnie's widow/manager] has been talking about reissuing [DIO's] 'Magica' album (originally released in 2000) with bonus tracks, including this one." Goldy goes on to say of the lyrics, that they were written by Dio when he was fighting cancer, and are "very emotional" and "hard to listen to without a lump at the back of your throat".
On April 15, 2013, Niji announced that a deluxe 2-disc version of Magica would be released on June 25, 2013. The first disc is identical to the original North American release (though it is remastered by Wyn Davis), but the narration track "The Magica Story", is moved to the second disc. The instrumental "Annica" (originally a Japanese-only bonus track) is also on the second disc, as well as "Electra," and six "Official Live Bootleg" (live recordings of Magica tracks). The ‘Official Live Bootleg’ songs were recorded between 2000-2002, at various dates on the Magica and Killing the Dragon tours. "Turn to Stone" was announced on the official press release for the Deluxe Edition, issued by Niji Entertainment Group, but was eventually omitted from the album, for unknown reasons.
In 2019, Magica was remastered and announced for reissue in 2020. Like the previous reissue it contains the track "Electra", but it is missing the instrumental "Annica". Furthermore, it contains nine previously unreleased live tracks.