First Appearance: LIAB Prologue 18
The three decrypted archons were a part of a force which croaked some of Charlie's units that entered Gobwin Knob battlespace. This event first tipped Charlie off to the significant change in Gobwin Knob's power structure (Wanda Firebaugh's attunement to the Arkenpliers and the resulting ability to decrypt troops, though Charlie would not learn that at the time).
Real World References
The names of the three archons are those of the Andrews Sisters, a famous American singing trio.