At the time of the beating Poi was three months into a three-year sentence for an attack where he reportedly bashed the back of a man's head with a bottle.
In May's trial Crown prosecutor Steve Manning described the victim as a "pretty green" prisoner who had found himself in the company of experiences inmates.
Poi had been part of an arrangement to smuggle drugs and tobacco into prison during a family visiting day.
Leota and Samoa's partners couriered the contraband to Poi's partner in Hawke's Bay who was meant to then bring it into prison with a friend during a visit on March 21 2015.
The drugs were instead thrown out the window of a car after the two women saw vehicles being searched as they approached the prison.
CCTV footage played in the trial showed Leota leading Poi into a cell just minutes after the family event had finished.
Moments later a convicted murderer, whose name is suppressed, carried Poi, who was lying unconscious in a pool of blood, to the guard house to get help.
During sentencing today Mr Manning said the "truly horrifying" beating had effectively ended Poi's life, or at least his quality of life.
He asked a sentence of preventive detention be passed as a finite one would not provide the court with assurance he would be safe to release on parole.
"This defendant's demonstrated and repeated brutality not just with this victim but previous victims is so serious that only a sentence of preventive detention will provide the community with the safety is needs," Mr Manning said.
Preventive detention is an indefinite term of imprisonment where individuals may be released on parole but remain managed by corrections for the rest of their life and can be recalled any time.
Defence lawyer Scott Jefferson asked for a finite sentence and noted Leota, who denied the offending up until the week of sentencing, had recently accepted the jury's verdict.
"The point is made ma'am that whilst he will spend the foreseeable [future] in prison the risk is a sentence of preventive detention would remove the light at the end of the tunnel."
Justice Clark began by acknowledging the presence of Poi's partner, the mother of his children, who provided the court with an "eloquent and moving" victim impact statement.
"She likened the effect of the injuries on Mr Poi to the effect of that on the family - shattered broken and fractured."
Poi now required around-the-clock care, suffered extreme fatigue and would never walk or talk again.
"You nearly killed him," Justice Clark said.
"[His partner] is left alone to witness the pain and distress of the children, being robbed of their father, while she deals with the loss of someone precious to her."
At the time of the attack Leota was serving sentences for two attacks on prison officers in Hawke's Bay and Auckland.
In April 2011 he punched a Mt Eden Prison guard in the face so hard he broke the officer's jaw in two places and, after two years of corrective surgery, it was reported he would never return to work.
Leota was later convicted of wounding the guard with intent to injure after a jury came to a unanimous guilty verdict in three hours.
At the time the Crown considered a preventive detention sentence but he was ultimately jailed for nine years.
Speaking after the sentencing yesterday, Poi's partner said she was happy with the outcome, adding it was better than previous sentencing decisions.
