The fan-favourite character will be reimagined for Keith Giffen and Tom Raney's new cosmic title.
Giffen has confirmed that Captain K'Rot, who was revealed in the solicitation for the third issue, is a new version of the anthropomorphic Superman analogue.
"Every book needs a borderline psychotic, booze-swilling, whore-mongering rabbit. I mean, c'mon!" he told Comic Book Resources.
The writer had previously promised that the series' "breakaway" star would debut in Threshold #2. The character is expected to appear on the final page of the issue.
The character originally debuted in New Teen Titans in 1982.
Threshold #3 will debut on March 13.