Complex sentence: He wears a helm with hair that he claims to have come from the mane of a griffon, although it is actually from a horse even though Flint has a "severe allergy" to horses.
Split into simpler sentences: He wears a helm with hair that he claims to have come from the mane of a griffon, although it is actually from a horse. Even though Flint has a "severe allergy" to horses.