Specialty is derived from Special. Specialty is related to Custom. Custom is related to Regular. Regular is a synonym of Weak. 
Troop is a type of Unit. Unit is related to Set. 
Special <--DerivedFrom-- Specialty <--RelatedTo--> Custom <--RelatedTo--> Regular <--Synonym--> Weak 
Troop --IsA--> Unit <--RelatedTo--> Set 