According to legend, Yanyun Eighteen Riders is a terrible ace cavalry unit led by Luo Yi. General * * * is composed of eighteen people, wearing cold clothes and holding machetes, wearing a mask on his face, wearing a black turban on his head, only showing his eyes, wearing a long black cloak outside, riding conference semifinals' riding boots with daggers, each with a big bow, each with eighteen arrows, and all with full moon machetes. Generally, they are active in the desert and rarely enter the Central Plains. They are elusive, all wearing masks, and no one has ever seen their true colors. Every time it appears, it will bring terrible killing to barbarians.

The above is from Baidu Encyclopedia, which also says that Yan Yun's eighteen riders were dissolved by his son Luo Cheng after the death of Se.

But what I know is that mccullough didn't dissolve him. Yanyun and McCullough rode on the battlefield together. In the battle with Liu Heita, McCullough was shot in the heart and died. Yanyun fought alongside him in this war.