In a rematch from a successful tournament fight earlier in the year, Kara started with left and right hooks, then got a knee through Robertson's defences, before they both started grappling and crashed down into the ropes.
Kara landed some more shots before getting caught by an overhand right to the top of his head.
Robertson swarmed out in the second round with kicks and smothering until a Kara knee backed up him, and that trend continued till the bell.
It was still anyone's fight and Kara started the final round well with a punches and kick combination, until Robertson again got in close and pushed them to the ropes.
With both men now tired, Kara connected clean with a straight right hand and then tied up Robertson, who got off one good shot before the bell but not enough to sway the judges.
Kara was mobbed in the ring by Awa Kings supporters after the decision was read out.
"It's cool, man. It's a real buzz, none of my other fights compare to today," he said on his seventh bout and first at home.
"That's the second time I've fought Jason. I knew he was going to come hard and come to get that win off me."
Kara said he would like to challenge for a North Island title at some stage this year, and thanked promoter Steve Alderton, trainer Lee Ashford, "secret weapon" Ivan Lacy and his Awa whanau for the support.
Barlow was left with sympathy for a brave Wilson but knew early on he was in a "mismatch".
"You know I take it serious," the former league representative said.
"I'm not here to experience it, I'm here to be better and improve."
Hard body kicks and followup punches had the young Taranaki fighter backing up immediately and Barlow stalked him into the corners, dropping Wilson for an eight count and then a seven count in the opposing trainer's corners.
A leaping knee blasted Wilson off his feet immediately after the second knockdown and the referee had seen enough.
Anderson's brutal victory left him with a tooth missing and his left eye swelling closed, but it was all worth it to pick up his first TKO victory over Henry Robertson.
After being tripped early, Anderson scored with high kicks, as Robertson went to the corners and either waited to counterpunch or would sway back in the ropes to absorb some of Anderson's power.
Robertson scored with leaping knees right up on the button in round 2, also getting another trip, before Anderson rallied with some pinpoint 1-2 jabs.
Another knee strike knocked out Anderson's mouthguard in the third round and when he turned away Robertson pounced with a series of blows, including an accident shot to the back of the head.
Rallying, Anderson blocked another knee strike and connected with body kicks, leaving Robertson doubled over, and then a leaping knee of his own landed and the Rotorua fighter was finished.
"My corner said I caught him off the knees, so I listen to my corner. Trust them," Anderson said.
Anderson carried to the ring a picture of his friend Johnny Kiely, who died in December and would have had his birthday last week. The pair met, and fought each other, when they were just 14 years old, and Anderson said his fighting career was carrying on what Kiely had started.