The initial hearing, conducted by video link from jail, was the public's first look at Anderson Lee Aldrich since the shooting and the suspect's beating by club patrons late Saturday night and early Sunday morning.
Colorado State Public Defender lawyers said in court filings on Tuesday Aldrich identifies as non-binary and prefers they/them pronouns.
Aldrich, 22, had been in a hospital from early Sunday morning until Tuesday, before being transferred to El Paso County Jail in Colorado Springs.
The defendant was handcuffed and wearing a jail uniform during the hearing.
El Paso County Judge Charlotte Ankeny ordered Aldrich be held without bail.
Though officials have not detailed the injuries, the suspected shooter was pummelled and pistol-whipped by Richard Fierro, a decorated former Iraq and Afghanistan war veteran, in a successful effort to stop further bloodshed at Club Q.
At least two others were also involved in kicking and subduing the suspect.
When Judge Ankeny asked the defendant to state a name, Aldrich, after a pause, uttered a barely intelligible response.
Aldrich also answered a pair of procedural questions "yes" and "no".
Defence lawyers declined to comment after the hearing.
Police initially held Aldrich on arrest charges of five counts of first-degree murder and bias crimes stemming from the Saturday night killings in Colorado's second-largest city.
El Paso County District Attorney Michael Allen said after the hearing he expected to file formal criminal charges at the defendant's next court hearing, tentatively scheduled for December 6.
In the meantime, Allen said his office would continue to ask that Aldrich be held without bail and that Aldrich's non-binary identity would have no bearing on how he would prosecute the case, including whether to charge hate crimes.
"I'm looking at evidence, evidence of what occurred here. That's what we look at when we make filing decisions," Allen told reporters.
The prosecutor also said Aldrich appeared physically competent to take part in the hearing, despite the injuries.
The five who died are Kelly Loving, 40, Daniel Aston, 28, Derrick Rump, 38, Ashley Paugh, 34, and Raymond Green Vance, 22.
