There's two other things I forgot to mention that prove Baelfael's power, both of which were only in the Japan release.
Baelfael's melee attacks were stronger. They actually stunned Bomberman (for the shortest of time, but again, handicap). This both displays power but also strategy, considering that stunning is better than damage given his arena. Bomberman can't swim so getting knocked in that water is lethal.
Baelfael also had a desperation phase at 2 HP, where he went crazy with the melee aggression. This puts Bomberman in an odd position, where he can only 'safely' dodge by wandering around the edge of the arena, but this is a danger in and of itself because he might off the edge or just get outright knocked off by Baelfael's stunning. So again, strategy.
But then there's just the sheer aggression of the phase. No other boss in the game has that level of aggression. Not even Regulus, who is made laughably predictable because he spams melee. Baelfael spams melee a lot too, but given his much smaller arena, it is actually more dangerous than Regulus doing it.
Baelfael is a stronger warrior than we thought.
Manfael? Or Baelwin? Baelfin.