In a Virus Control Deck, this card's summoning effect can be troublesome for your opponent. If your opponent activates a Spell during their Main Phase, they run the risk of having their cards destroyed.
Two of the most powerful monsters you can summon with this card are "Infernal Dragon", with 2000 ATK, and "Rare Metal Dragon", with 2400 ATK. However, both of these monsters have severe drawbacks. "Infernal Dragon" is destroyed during the End Phase if it attacks, while "Rare Metal Dragon" cannot be Normal Summoned or Set. By using "Dark Horus" to summon these monsters, however, you can erase their weaknesses and use their raw attack power to take huge chunks out of your opponent's Life Points. If "Mystic Plasma Zone" happens to be in play, those Monsters can be used to play "Eradicator Epidemic Virus".
Use this card's effect to summon "Lady of D." to guard this card from attacks. Summoning "Obsidian Dragon" is also a good choice to prevent this card from being targeted