SIA is Invader Zai's SIR Unit. She got quite a bit of brain-chip damage during Zai's crash landing, and Zai quickly tried to repair it. Emphasis on the word tried. She ended up making SIA live, but since Zai isn't that good with robots, so she caused SIA to be insane and wacky.
SIA likes to eat cookies, Pop-Tarts, burritos, and sometimes soap. She really dislikes fish, saying that they are "slimy and blucky". She also doesn't like chicken nuggets because...well, nobody knows. She just says that she "just plain don't like 'em!"
SIA can be very childish, playful, and very, very random. (Ex. Takes out lobster from head and runs around shouting "SMOOTHIES!!!") Normal people don't really notice her strange behaviour when she's in poodle costume, they just go 'Awwww' when she does something playful.
SIA never goes into 'duty mode', unless she sees her master in a really fatal situation. Her eyes will then turn red, and rush to do her best to protect her master.