Fengalon is the Wind Guardian. He looks like a great white tiger and is one of the most frequently appearing Guardians in the series.
In Wild Arms 4 he is known as Code F and is a Guardian Drive that can be summoned from the Wind (green) leypoint in a HEX field. In Wild Arms 5, he has a wind-elemental TF System tower named after himself, known as "Tower F".
Wild Arms 4 is the only instance in which he does not appear as a white tiger. Rather he appears to be some sort of dinosaur creature similar to a raptor.