The best part about fauxcest ZenDabi is that it's never close enough for either of them. It's close, but not close enough. Touya's hair's white like Yoichi's but it's too short. His eyes are just a couple shades off. His body's close enough but there's more scar tissue. Zen's big like Enji, but he's bigger. His hair/eyes (before his facial injury) don't match color wise but it's almost close enough. His voice is deep and firm like Enji's but different in a way Touya can't place. They're both so close, close enough that if they squint they can pretend but it'll never be just right. Touya won't ever be Zen's Yoichi and Zen won't ever be Touya's Enji. They can pretend but they'll always see the differences and it'll never be enough because they can never truly replace the most important person to them.