No problem with the Sense! Esteban would likely be likened to fire/flames, but it might be difficult to pinpoint what he is, being a half-elf, half-dragon.

He is a little old for his appearance, but not overly so; his soul might also feel young if Ryo believes in reincarnation.

One thing Ryo might notice is that he is NOT a demon or a devil! if he has any frame of reference. This is pretty important to Esteban because he LOOKS like one when he shapeshifts, hence why he is pretty discreet about his shifting abilities.