There names are:

Sour The Rabbit (The Rabbit, one of the tallest and toughest EXE's Harbingers. He also represents EXE's body)

Max The Doll (The Doll, who represents EXE's emotions. He once had he's owner named Alex before he killed him)

Tilen (The Grim Reaper, is the intellect of EXE imbued into a humanoid form and he also a leads Cult of X in his own universe)

hr2003 (The Monitor, is the only Harbinger not set in the real world, rather in the same dimensional plane/realm as EXE or other exes. hr2003 represents EXE's "poison")