Uh... since Healie somehow won last week... and is currently winning 2-0 at the moment... Whiskey Tango Foxtrot, unless remake Healie is uber or something. For Big Joe, I could vaguely understand, because maybe some people deny him his crowd (though.. it kicks in sometimes even if you don't deathblow, and seems about as legal as various other seemingly other "environmental" effects for other duelers, and Joe might win without a crowd anyway if you hold Healie to his horrible AI that heals early and spends turn defending). But... any Fire Emblem character? Both Fire Emblem and Dragon Warrior IV are subtractive defense games. As a reminder, Healie does 1-2 damage at best to enemies, and enemies with good defense (like Saro's Shadow) get a "miss," i.e. no damage due to defense entirely nulling the attack. The rest of the cast at the end of their chapters is doing way better damage, 20-25 at least, meaning Healie has something like 20HKO damage at absolute best (that's using 3 damage). Unless Jagen has a defense score of *0*, Healie's attacks are tinking here. And if you don't allow subtractive defense, and let Healie have perfect AI, if Jagen has anything approaching offense Healie won't be able to do a whole lot other than heal due to his miserable HP and defense as well.
I haven't played Shadow Dragon, but basically Jagen needs to be Euram-level competent to lose this one, at least to original Healie.