Bacchus had a huge army of guards. He had his personal guard cover 2 whole floors on his towers and still have a large amount of men to defend him as well as the needed weaponry to arm them.
Bacchus, being the mayor, is very wealthy and has sufficient funds to hire a small army of personal guards in preparation for the survival game. He has what appears to be several hundred guards which defend his super computer. He used his money to equip them well with guns. This small army is directed by him using the The Watcher diary which allows him to know the other player movements and relay them to his men. The guards are extremely cold blooded and have no problem killing civilians or even children.
Kurou Amano is involved when John begins to make his move against the other diary owners, manipulating Kurou Amano into his services by telling him that if he destroys yukkii's diary, his debts will be cleared. However Kurou fails because of the interference of Marco Ikusaba and Ai Mikami who had used a fake cellphone to mislead yukkii and Yuno, saving yukkii in the end when Kurou breaks the fake instead of the real one.