How is 臣 from? It is very lonely in Chinese!

How is 臣 from?

臣 chén, originally meant “male slave”, is a character with very little “siblings” in Chinese characters. Totally, there are only seven characters composed of 臣: 

卧/臥 wò; 临/臨 lín; 藏 cáng,zàng; 臧 zāng;  臤 qiān; 臦 guàng; 臩 guǎng. Only these three are commonly used: 卧/臥 wò; 临/臨 lín; 藏 cáng, zàng.

文言版《説文解字:臣,牽也。事君也。象屈服之形。凡臣之屬皆从臣。  

白话版《说文解字》:臣,被牵拉。表示侍奉君王。字形像一个人屈服之形。所有与臣相关的字,都采用“臣”作边旁。