Xiahou Lan

Xiahou Lan was an acquaintance of Zhao Yun from childhood. His degree of kinship with Xiahou Dun is uncertain.

Battle of Bowang
During the Battle of Bowang, Liu Bei's general Zhao Yun captured him (Xiahou being a general of Cao Cao), and despite their close tie, turned him in to Liu Bei but pleaded for his life and recommended Xiahou to be a military judge, to which Liu Bei, after careful consideration, agreed. To avoid raising further suspicion, Zhao Yun did not approach Xiahou Lan ever again.

In fiction
In chapter 39 of Luo Guanzhong's Romance of the Three Kingdoms portrays Xiahou Lan being killed by Zhang Fei in one thrust of his spear while he were trying to save the fodder in Xiapi.