The band was formed around 1995 as a continuation of Festerday. They recorded two demo tapes, "Wave" (1995), which was never officially released, and "Mare Liberum" (1997), which was released by Swedish Defender Productions. This led to a record deal with Season Of Mist which released their first three albums; "Dynamic Gallery of Thoughts" and "WAR Vol I (split with Bloodthorn)" (both 1998) and "The Symmetry Of 1, The Circle of O" (1999). After this they signed to Century Media and released "Allotropic/Metamorphic - Genesis of Dimorphism (A.M.G.O.D.)" (2001) and "Cypher" (2002), which is their last album so far.
The band hasn't really had any line-up changes, but the members have changed their names/pseudonyms few times.
In 2005 the band changed name back to Havoc Unit.
In 2013 they called themselves again Festerday.
In 2017 they reformed again as …And Oceans and in 2018 played live for the first time in 13 years.