i always thought a clan is a fun group in similarity to what flowey said, but i think a clan should have a good talent or purpose for being there, like one is good at something. take for example building or coding or etc. i thought a clan like that would totes be fun and interesting
and if you want to make a type of clan that goes at war (hopefully not fully hate one another) with other clans then you can do that too, but just don't get to your boiling point if you know what i mean