In "101 Mitigations", Comic Book Guy had plastic figurines of Bean, Elfo, and Luci, among all the other pieces of garbage in his room. Homer noted that this, along with everything else was "a collection of stuff someone else threw away".
Elfo is a lime-colored elf hybrid that is short in stature and has a pig-like snout. His ears are pointed, in reference to the common trope. He has messy hair and an angry complexion. He has a large overbite, with a wavering lip. He wears a brown vest with a v-neck that is opened to reveal his neck. he wears short blue shorts and has spiky brown shoes, possibly to hold his feet which may curl up on the toes. He has four fingers, unlike the humans with five, and the Dankmirians with three.
Elfo begins by being dissatisfied with life in Elfwood. For him, something does not seem quite right. He has had enough of being happy all the time - suffering the elvish equivalent of depression. Making candy all day to get paid in candy just doesn't make sense to him anymore. As such, he is savvy of his own genre and has outgrown his elven tropes. He craved freedom and adventure. To that end, he desires to see the outside world, despite how unscrupulous and miserable it may be.
Once outside of the kingdom, Elfo is shown to be both excitable and naive: he is excited to be embarking on a new adventure, but naive as to what to expect. He is definitely not savvy about the world beyond Elfwood - asking a gnome "what is war?" - but his elvish disposition makes him optimistic in the face of danger: that and the fact that he has lived a sheltered existence and doesn't know what to be afraid of or who to trust. Given his mixture of traits, he could be described as happy-go-lucky meets devil-may-care.