EF-XB2006 was created by Dr. Eggman as one of the most recent models in the Egg Fighter robot line. Because of his recent creation, however, EF-XB2006 had much to learn about the world and as such, devoted most of his time to studying.
During the events of Sonic Unleashed, EF-XB2006 came across Sonic the Hedgehog and Chip when they arrived in Eggmanland. Upon meeting the duo, EF-XB2006 told Sonic and Chip about his need to learn, before requesting Sonic to converse with him so that he could improve his cognitive processes. As Sonic accepted the request, EF-XB2006 began a sequential conversation with Sonic on various subjects, examining Sonic's responses. At the end of the conversation, EF-XB2006's examination was complete and he began to analyze their conversation, reconfiguring his personality accordingly so that he and Sonic could be friends. After having demonstrated his new personality to Sonic, EF-XB2006 asked Sonic if his personality fit him and if they could be buddies.
As one of the newest Egg Fighter robots created by Dr. Eggman, EF-XB2006 lacks a lot of world experience. As such, he spends most of his time studying in order to define his personality.
- The "XB2006" in EF-XB2006's name is a reference to Sonic the Hedgehog (2006), which was released for the Xbox 360 in 2006.
- By talking with EF-XB2006, it is shown that it will reformat it's personality to make it more likeable to whomever it speaks with given enough interaction. However, EF-XB2006's personality edits end up making it less appealing to anyone it has previously spoken with, not to mention these personality tweaks only last several seconds before forgetting them.