Decrepit Birth is an American progressive/technical death metal band. Originally a brutal death metal band with a straightforward early-2000s Unique Leader Records sound, they took a far different turn with their second album, focusing on highly complex, melodic, and multifaceted arrangements highly reminiscent of late-era Music/{{Death}} and with it has come a great deal of fame that is steadily propelling them into the upper echelon of modern death metal.

The band was formed in Santa Cruz, California in 2001 by Bill Robinson (vocals), Matt Sotelo and Mike Turner (guitars), and Derek Boyer (bass). A drummer was not found, however, and the band stayed a studio project, drafting Tim Yeung for session drums on ''...And Time Begins'', their 2003 full-length debut. Boyer left soon after to join the reunited Music/{{Suffocation}}, and the band quickly found a replacement in Risha Eryavec. More significant, however, was their acquisition of a full-time drummer in the form of Bay Area drumming extraordinaire KC Howard (of Odious Mortem fame). The next year or so went by uneventfully, though Sotelo was busily engaged in writing material for a promo that would serve as a sampler of their new sound. 2006 proved to be one of their biggest years in more ways than one; on one hand, the promo dropped and instantly gained a sizable amount of critical praise, but on the other, Mike Turner was found guilty of child molestation charges that same year, which resulted in his unceremonious ejection by a disgusted Sotelo. No attempt was made to find a replacement; besides, they were too busy writing for and recording their breakthrough album. That album, ''Diminishing Between Worlds'', dropped in early 2008 and was instantly hailed as a modern classic, and in its wake came multiple slots on high-profile tours. In addition, the band finally found another full-time bassist in the form of Joel Horner, as well as Dan Eggers, Turner's replacement and a renowned guitarist in his own right.

2009 brought even bigger things by way of a spot on the Summer Slaughter Tour, along with other lucrative large-scale tours. The band made a return to the Summer Slaughter lineup that same year, supporting ''Polarity'', their newest full-length. Howard, however, left the band and retired from touring altogether, choosing to focus on tutoring and session work instead, with Eggers soon following. Eggers was quickly replaced by Chase Fraser, while Howard's spot was filled in live at various points by Sam "Samus" Paulicelli and Lee Smith until the former finally joined full-time (barring college). Horner left the following year, with Boyer briefly returning until Suffocation called him back, resulting in Sean Martinez taking over his spot in turn. More touring followed, with [[Music/{{Arkaik}} Alex]] [[Music/{{Trivium}} Bent]] and [[Music/{{Alterbeast}} Gabe Seeber]] taking over as needed when Samus' college obligations took precedence. As of now, the band is writing for a new album; according to a reply to a question about the release date on their official Facebook page, an early 2016 release is on the horizon. Additionally, Chase Fraser left or was fired at some point in 2015, and a replacement has yet to be announced; meanwhile, longtime live bassist Sean Martinez has been made an official full-time member and will be performing on the new album.
* ''...And Time Begins'' (2003)
* ''2006 Promo''
* ''Diminishing Between Worlds'' (2008)
* ''Polarity'' (2010)
* ''Axis Mundi'' (2017)
The band provides examples of the following tropes:
* AscendedExtra: Sean Martinez.
* BigFun: Matt Sotelo
* [[DeathMetal Brutal Death Metal]]: ''...And Time Begins'' and ''Axis Mundi''.
* CoverVersion: They have covered [[Music/{{Death}} "See Through Dreams" and "Crystal Mountain"]] (the latter having only been covered live thus far), [[Music/{{Metallica}} "Orion"]], [[Music/{{Sepultura}} "Desperate Cry"]], and [[Music/{{Suffocation}} "Infecting the Crypts"]].
* EpicRocking: "Essence of Creation" and "(A Departure of the Sun) Ignite the Tesla Coil" are tied at 6:34.
* EruditeStoner: Bill, though he abstains from weed usage during and around tours to preserve his voice (and also to avoid hangups at border crossings).
* IAmTheBand: Matt Sotelo
* LeadBassist: Sean Martinez is a Type A, while A.J. Lewandowski, despite merely being a one-time live session player, doubles as a Type C due to his well-known YouTube channel, which is how he got the spot in the first place.
* LeadDrummer: Samus Paulicelli is known for his rather infamous YouTube channel. He's also apparently contributed a fair bit to the songwriting process for ''Axis Mundi''.
* LoudnessWar: A problem on all their releases, which is particularly jarring on ''Polarity'' given the amount of soft instrumental passages.
* MetalScream: Bill is a solid Type 2.
* MotorMouth: Bill does this every now and then.
* MinisculeRocking: "A Brief Odyssey in Time" tops it at 1:03, while "Prelude to the Apocalypse" isn't far behind at 1:25.
* MohsScaleOfRockAndMetalHardness: Hard ten on ''Time'' and ''Axis'', soft ten on ''Diminishing'', and an equal split between a soft ten and a hard nine on ''Polarity''.
* MushroomSamba: Their sole lyrical theme by way of Bill's psychedelic experiences.
* NewSoundAlbum: Every single one:
** ''Diminishing'' was a complete change of sound into a proggy tech act very reminiscent of later-era Music/{{Death}} and Monstrosity.
** ''Polarity'' dialed down the tech elements slightly and went in a far more prog-oriented direction.
** ''Axis Mundi'' is a bit of a throwback to the classic Unique Leader brutal death style present on ''...And Time Begins'' with the flashier elements of their later material intact.
* NobodyLovesTheBassist: They've had some famous names in their ranks over the years, but most of them have been live session players. Joel Horner was a full-time member, but when he left, they didn't bother to find a full-time replacement and just drafted people as needed. Sean Martinez has averted this, as he has been a full-time member for quite a while and tracked his own parts on ''Axis Mundi''.
* ProgressiveMetal: ''Polarity''.
* PurpleProse: Common within their lyrics, particularly in their post-''Time'' material.
* RapunzelHair: Sean Martinez, and it's made his windmills quite famous.
* RevolvingDoorBand: For a while, but things have been relatively stable recently. At this point it's Bill, Matt, and Sean, with Samus only making studio contributions (as he currently cannot tour), and Gabe Seeber handling most of the live drumming (aside from tours that he can't make because of The Kennedy Veil) until (if) Samus's school and work obligations allow him to play shows again.
* TechnicalDeathMetal: ''Diminishing'', mostly.
* TrueCompanions: With Music/{{Suffocation}} and Odious Mortem; three out of the four members of the latter have been in Decrepit Birth as well, with Anthony Trapani being the lone holdout.
* SignatureStyle: Winding, intricate compositions with an airy, spacy feel, lots of melodic soloing, and lots of extended instrumental jams.
* SpecialGuest: [[Music/Powerman5000 Ty Oliver]] has contributed guest solos on ''Diminishing'' and ''Polarity'', and they've had a whole lot more if you count all the live session bassists and drummers they've gone through.
* ThisIsUnforgivable: The band's reaction when they found out what Turner had done.
* WalkingTheEarth: Bill has been voluntarily homeless for over twenty years and lives off the grid in a hut that he built himself.
* WordSaladLyrics: Occasionally.