舎弟

1. Origins, structure, and basic meaning

• Structure: 舎弟, read しゃてい, refers here to a sworn younger brother or a subordinate in that relationship.
• Basic usage: It expresses brother-like ties and hierarchy between characters in a story.

2. Common pitfalls and similar expressions

• Do not assume a blood relationship
  • The example describes exchanging cups and 舎弟にした, taking someone as a sworn younger brother. In this context, he is not a biological younger brother.
• Compared with an ordinary subordinate
  • Compared with 部下, it suggests a brother-like bond or the hierarchy of a particular group. It is not a general label for an ordinary workplace subordinate.