Zane Benson Williams, better known by his stage name Riko Dan and formerly by the mononym Riko, is an English multi-genre MC from Mile End, East London. He rose to prominence in 2004 as a member of the pioneering grime collective Roll Deep, of which he remains an active member, and is also established in other sound system genres including bashment, jungle, and dubstep, with a prolific discography as a featured artist. He has charted on the UK singles chart with the 2024 Rudimental, Skepsis and Charlotte Plank collaboration "Green and Gold".

Williams has performed as an MC since the age of fifteen, when he would rap over breakbeat hardcore at house parties and later jungle on pirate radio. He used various aliases in his youth including Zany Ranks, Zany Banton and Joox before settling on Riko, in honour of a friend of the same name who died in a car crash. In 1994, his first radio show saw him MCing on Pressure FM in Bow with the station's founder, Jamie B, as the DJ. The show was on Sunday evenings, considered the best time slot of the week, and it helped Williams to gain recognition among the hyper-local audience within range of the station's transmissions. Through Pressure he also met fellow resident and future collaborator Slimzee, the co-founder of Rinse FM. He gained minor recognition as a regular performer on Rinse.

Williams had befriended multiple members of Bow-based UK garage group Pay As U Go at the age of about sixteen through family ties, prior to the advent of garage, and has claimed he would have likely been a member earlier had he not been incarcerated. He served time in jail for commercial robbery between 1999 and 2002, joining the group once its sound had shifted from garage to the then-unnamed grime genre and members Wiley, Flowdan and Maxwell D had left to form their own crews. In early interviews, Williams emphasised that he wanted his music to encompass many genres including grime, garage, and bashment. The months following his release were musically prolific and he recorded "about six" tracks for a Pay As U Go album, but within "about seven or eight months" of him joining the crew, it disbanded.

Williams' first credited appearance as a solo artist was on the Nasty Crew single "Cock Back" alongside Crazy Titch in 2003. He has claimed that he was asked by Marcus Nasty to join the Newham-based crew but declined due to his ties to Bow. Other songs recorded during this period included a version of Ruff Sqwad's "Pied Piper", features on the single "Poppadoms" by Rinse FM founder Wizzbit and the OT Crew song "No Games" alongside God's Gift, and a diss track over Wiley's "Igloo" instrumental directed at More Fire Crew's Neeko. Later the same year, Williams was recalled to jail, serving a further nine months in HMP Weare for a separate historical 1999 burglary. He penned an open letter to fans in Deuce Magazine, in which he claimed that "When I am out at the end of the year, my plans are to get my career back on track, finish off my album, slew Neeko again and again and again, oh yeah and get my own column in Deuce every month!"

Williams joined Wiley and Flowdan's pioneering grime collective Roll Deep in 2004, first appearing alongside the full crew on "Flame Grilled Whopper", having already collaborated with Wiley on a solo vocal version of "Ice Rink". DJ Target produced his debut solo single, "Chosen One", which was released in 2004. He featured prominently on Roll Deep's 2004 Creeper mixtape series, in which he continued to diss More Fire Crew, and recorded another single for Target's Aim High label, "Critical" featuring Dogzilla and Discarda, which ultimately appeared on an Aim High compilation. By November 2004, he had been remanded to HMP Brixton to stand trial for another alleged offence, and recorded a verse for Lady Sovereign's "Random" remix over the phone. The case against him was dropped in late December 2004.

Williams appeared on the bonus track "Poltergeist (Remix)" on Roll Deep's 2005 debut album In at the Deep End, which entered the UK Albums Chart at number 50 and marked his chart debut. As part of Roll Deep, he also appeared on Top of the Pops, providing backing vocals on a 2005 rendition of "The Avenue". The same year, he featured on D-Power Diesle and Doctor's single "Come On", which appeared prominently on music video television channel Channel U and was listed by specialist London record store Rhythm Division at number nine on its chart in June 2005. During this period, he began recording a prospective debut solo album for Sony Music, which was to include the previously released songs "Dead That" (featuring God's Gift) and "Don't Want You Back" (featuring Breeze), but the plans for a record deal fell through when he returned to jail in 2006. His charges were dropped after eight months and many songs recorded during this period instead appeared on his debut mixtape The Truth Vol. 1, released independently via Roll Deep Recordings in 2008.

Williams went on to appear on all Roll Deep albums except their pop rap albums Winner Stays On (2010) and X (2012), for which they involved a smaller number of members. He released his second solo mixtape, Sleeping Giant, in 2010 via Billy 'Daniel' Bunter's label, Slaughter House Rydims, through which he also released the extended plays Blowing Up Again (2010) and Warfare (2011). He had been introduced to the label by his then-manager, long-standing Rinse FM DJ Uncle Dugs. Slipmatt was credited as a mixing engineer on the lead single for Sleeping Giant, "The Phone Call". After becoming a father, he "put [music] on the backburner for a year", before featuring on the title track of Terror Danjah's 2012 album Dark Crawler and releasing a 2013 surprise mixtape, Rise of the Farda, via Logan Sama's Adamantium label.

In the mid-2010s, Williams began experimenting in recording what he has described as "dark" and "abstract" bass music, collaborating with record producers such as Rabit, Mumdance and Ziro. The most commercially successful of these were Wen's 2015 single "Play Your Corner", which peaked at number 96 on the UK Physical Singles Chart, and The Bug's 2016 single "Iceman", which appeared on a double single also featuring D Double E and reached number 23 on the same chart. In 2018, he released the Hard Food EP on Pinch's record label Tectonic, marking the label's hundredth release. The following year, he released a pair of grime singles, "CR7" and "Farda", via Logan Sama's labels Keepin' It Grimy and Adamantium.