Suggested by Destroyer Diaboromon was capable of taking on two Mega Digimon at once. Granted he got a speed boost but in general this is a top tier fighter with a lot of speed and great attack power. Lucina has a lot of range in her attacks and speed of her own but ultimately I don’t think it will be enough here. Getting past his energy blasts will be difficult enough and she will be weakened by the time she’s in a position to deal damage. Diaboromon wins.