Black retires from the Federal Bureau of Investigation and moves his wife Catherine (Gallagher) and daughter Jordan (Tiplady) to Seattle, where he begins consulting on criminal cases for the group.
[3] Television critic Robert Shearman said that the series featured "half a dozen actors who could be termed regulars [...] but without exception they remain functional ciphers".
[6][7] Before they can reconcile she dies in a viral outbreak initiated by the group, who are trying to bring about the end of the world, and Black returns to the FBI to pursue them.
Black is framed for the death of a fellow agent, prompting his resignation from the FBI and flight with Jordan to Washington D.C., and Hollis abandons him to work with the group.
[10] Several years later, Black works with FBI agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) to foil a last-ditch effort by the group to orchestrate the end of the world; vindicated, he reunites with Jordan after the case.
[11] Millennium's creator Chris Carter conceived of Black as an archetypal Western hero, describing him as "self-reliant, quiet, capable, dangerous" and comparing him to the title character of the 1953 film Shane.
[12] Although William Hurt was considered for the role early in casting, Carter denies that he was seriously approached for the part and calls Henriksen their "first and last choice".
[13] Producer John Peter Kousakis noted that Black was the constant throughout the series, as each season featured changes in tone and plot.
Gallagher found it interesting for her character to give up her life for her daughter after the series had focused on Frank's sacrifices for his family.
[29] About Hollis, producer Michael Duggan said: "She's not a rookie ... but she's young enough to be in awe of Frank Black's rep as a legendary crime solver".
[32] Scott's acting in the role was praised, with critics calling her "bracing"[33] and noting that she "works hard to mine some sort of truth" from Hollis' character.
[34][35] Andrews turned on fellow group members Black and Watts during an internal schism, unsuccessfully trying to steal a holy relic for her faction.
Club's Zack Handlen noted that she "manages to put herself across quite well" despite the difficulty of standing out from the series' sombre tone.
"[40] Aloof and arrogant, FBI special agent Barry Baldwin (Peter Outerbridge) works with Black and Hollis on several cases.
[9][41] During an FBI raid on the home of a serial killer whose brain was altered by the Millennium Group (triggering his killing spree), Baldwin is injured in an explosion.
[46][49] She later reappears as a succubus, sexually assaulting Black in his sleep to frame him for rape and (as a large snake) trying to kill Emma Hollis.
[52] Robert Shearman and Lars Pearson, in their book Wanting to Believe: A Critical Guide to The X-Files, Millennium & The Lone Gunmen, found the character a good balance of the depictions of evil throughout the series:[53] "something very strange and new and terrifying".
Initially wary of Black's unorthodox approach to offender profiling,[5] he comes to value his insight and seeks his help with difficult cases.
He noted that although the "hard-boiled detective" Giebelhouse represents seems clichéd, he felt (from his law-enforcement research) that type of character was "very real to life".
[8][58] Means' character was created by second-season executive producers Glen Morgan and James Wong to "both challenge and reflect" Frank Black.
[64] O'Quinn described his time on the series as "rewarding", noting that his character often provided narrative exposition because Henriksen dislikes expository dialogue.