Tyrone
Tyrone is a made-up figure within the Larsonverse, He is a manifestation of an intimidating figure created by trolls, typically used universally by anyone to harass Daniel.
He is also one of the most influential fake characters to Daniel Larson. At the moment Tyrone is supposedly Grace VanderWaal's Bodyguard. However, during the July 24th Freak-out He was allegedly trying to kill Grace.
Encounters
Some of Daniel's first major encounters with Tyrone was during the July 24th Freak-out where he was seen by Daniel trying to kill Grace Vanderwaal by "Shooting her in the shoulder and abdomen".
and on the August 29th Meltdown in which a fake Grace VanderWaal states to Daniel that she will have Tyrone kill him- by butt-fucking Daniel to death.
Background
Because Tyrone is not a real person, we really don't have too much information on him. However, he is hell-bent on destroying Daniel on Grace's orders. It is possible that the Tyrone persona is played by different trolls.
Some people claim that "Tyrone," a fictional character, is targeting him due to his proven pedophilic behavior.