A teenager who burned his clothing after a town centre stabbing, which left his victim needing surgery and permanently scarred has been spared immediate custody.
As Kempster, then 18, ended up on the ground, he used a pen knife to slash and stab 19-year-old Billy Tomlinson.
The victim suffered a puncture wound to his left thigh but, more seriously, the knife also went through around a third of his bicep, severing a sensory nerve.
Mr Tomlinson underwent a four-hour operation and had to wear a cast for a month.
Although the injuries had healed with weeks, the court was told two "nasty scars" remained.
And in a statement, Mr Tomlinson had described the ongoing impact of the attack, particularly on his girlfriend and family; of being "on edge" and his social activities being curtailed.
Of Kempster in the aftermath of the attack, prosecutor Brendan Burke said: "He fled the scene, burned his clothing but handed himself in the next day."
Kempster, of Gillinggate, Kendal, admitted unlawful wounding and possession of an offensive weapon.
Jacob Dyer, mitigating, spoke of previous online issues between Kempster and one of the two other young men.
At the time, Kempster accepted he was using cannabis and had been "a little paranoid" about the earlier internet exchanges.
Mr Dyer said it had been a chance meeting with no premeditation, adding: "He made a bad decision.
"He was on the ground, he produces a knife and obviously lashes out with that and causes the injuries."
Passing sentence, Recorder Peter Horgan stated: "The use of knives to cause any form of assault or injury is one that the court will not tolerate."
But Recorder Horgan concluded there was a realistic prospect of rehabilitation and that he could "just" suspend 21 months' imprisonment for two years.
This was in view of his age, efforts made since the offence, mental health difficulties and the fact he appeared to have "settled" and was pursuing a college IT course.
Kempster must complete 200 hours' unpaid work, a three-month night time curfew and was banned from contacting the other three young men for five years.
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