Wikipedia
Pseudocommando
In forensic psychiatry, the term pseudocommando has been used to describe mass murderers who commit premeditated murder-suicide mass killings driven by revenge fantasies, typically involving the stockpiling of weapons followed by a heavily armed commando-style attack.
They typically see their actions through a narcissistic lens as being morally justified in revenge against their unfair treatment by an uncaring world, and wish to "go out in a blaze of glory".
Some observers have divided mass killers into three categories: pseudocommandos, family annihilators, and hit-and-run killers.