I believe Golden Resurrection is another band he joined. This song was written by Tommy when he was 14 years old and for his band ReinXeed (now Majestica).
I'm quite impressed with Tommy. I seen in the comments that he wrote this song when he was 14. I loved seeing the different pictures of the band members. That was neat. Great reaction.
I don't know about Tommy's personal believes, but Majestica (ReinXeed) was never a Christian band, it's typical symphonic power metal. He was part of the Christian metal band Golden Resurrection but that band fell apart. I recommend listening to newer Majestica song Above The Sky and Ghost of Marley from their Christmas Carol album