From ErfWiki

Contents 1 Proposed Canon 1.1 First Appearance 2 Speculation 2.1 Known users 2.2 Real World References

Proposed Canon

A non-humanoid flying unit - specifically a bird, with a vague resemblance to a snow owl.

First Appearance

TBFGK 9

Speculation

Apparently a fairly weak unit, with limited combat capability.

Known users

Royal Crown Coalition

• Jetstone

Real World References

The name originates from a famous Internet meme of the same name which means "Oh, really?". Orlies' exclaimations primarily feature similar phrases. On Page 114, Panel 2^Erf-b1-p114, the Orlies hold a conversation in Leetspeak:
"Seriously." (SRSLY)
"Oh, really?" (ORLY)
"Hahaha... what?" (LOLWUT)

Known exclamations are:

• ORLY?^Erf-b1-p009 -- Oh, really?
• YARLY!^Erf-b1-p010 -- Yes, really.
• LOL^Erf-b1-p010 -- I'm laughing out loud.
• OMGWTFBBQ!^Erf-b1-p012 -- Oh my God! What the fuck? Barbecue!
• PWNED!^Erf-b1-p012 -- Owned! (I win!) (Or, in context, I lost!)
• O HAI^Erf-b1-p094 -- Oh, hi.
• SRSLY^Erf-b1-p114 -- Seriously.
• LOLWUT?^Erf-b1-p114 -- Hahaha... what?
• G2G DED!^Erf-b1-p114 -- Got to go, because I'm dead.

There is also a real bird with a similar name, the Oriole. However, has no other resemblance except the name.