Great reaction! This song is a thank you to all their fans, And they wanna share the bond the band members have with each other. So they bring in their kids, HammerFall is actually older than Battle Beast, they started in 1993, and they are more Heavy Metal than Power Metal, because of how old school it sounds but modern, They have released their 12th album, this song included is the opening song, Fun fact HammerFall and Noora Louhimo has a song together called "Second to One", They sing alot of Hell, but its awesome, If you listen to Brotherhood 2-3 times more, its gonna be super catchy

The girl (Joacim's beautiful daughter) who singing at the end it's a melodic reference to the song Reveries on the also last album Hammer of Dawn. Heavy Song!

Hell yeah! More of HammerFall! :D Im sure you've heard their song Hearts On Fire! Fun fact? They are celebrating the 20th anniversary of the album containing that song this year, so maybe check that out, see if you know it?