Complex sentence: Solstice ended their 12 year absence from the recording studio in early 2013 with the release of their Mini LP "Death's crown is victory" which was their fastest selling selling release, and was issued on their own "White Horse" imprint.
Split into simpler sentences: Solstice ended their 12 year absence from the recording studio in early 2013 with the release of their Mini LP "Death's crown is victory", which was their fastest selling release to date. This was issued on their own "White Horse" imprint.