They were walking on the beach together when they met Blackbourn and a friend.
Ellis, now 30, had said something like, "Hey, I know you from somewhere." A distant connection was enough to get chatting.
Hall carried on alone, and 10 minutes later an excited Ellis caught up and said: "Hey, I got her number."
Hall said Ellis had always been one for "whirlwind romances".
"He wouldn't give it long enough before he started talking about love and marriage and babies. All too often the girls would be freaked out by that and run a mile."
As a recovering addict, Ellis tried to avoid alcohol but Blackbourn still liked to go nightclubbing or have a glass of wine at home.
They broke up after he tried to stop her going out one night. Police said he punched her in the head and neck before throwing her into a table.
"He fell apart immediately," said Hall. Ellis' history of violence against previous partners crept up on him. In court, two women told of his temper. One woman, who was with Ellis when he was 18, said he'd broken into her house and frightened her and her young daughter, ripping the phone from the wall and shouting they were meant to be together. Another said he'd thrown a TV at her, causing her to fear for her life.
Police said from April 26 to her death in June, Ellis sent Blackbourn about 800 texts, mostly saying he couldn't live without her.
On the day she died, Ellis had been drinking heavily. He went to her house with a knife, raped and stabbed her, then poured fuel on her and set her alight.
Court documents state Ellis grew up in a supportive family in Torbay. He began experimenting with alcohol at age 8, smoked cigarettes at 11 and tried dope at 13. In more recent years he moved on to methamphetamine, ketamine and cocaine. By age 27, he was using cannabis and a gram and a half of methamphetamine every day.
Hall remembered seeing him collapsed in an Albert St gutter on the way to work one day. "I bundled him into the car, took him home, washed him, sobered him up, gave him a good feed, let him sleep on the couch for a couple of weeks, got him talking to his parents again - this was something that happened maybe a dozen times over the course of me knowing him."
He said it was sad that that support was all for nothing.